Student Site Map

Math
Vocabulary & Concepts



addition (regrouping)
algorithm
area

finding the area of a square or a rectangle

using Factoring Chart to find rectangular dimensions

base-ten language
broken-line graph      
chance          
circle graph
circumference        
composite number
conversions
         fraction - decimal - percentage
         units
coordinates
decimal
         adding decimals
         multiplying decimals        
divisor
division
         showing remainder results in two ways
estimating
expanded notion number
even number
factor number
         factor chart
         factor tree
flip
frequency diagrams
fraction
graphing
         t-tables
         weekly graph
         conversions
height         
intervals         
irregular shapes      
line plots   
mass 
mental math
multiple 
multiplication
         using arrays (or grids)
         using expanded notation
         decimal numbers
number patterns
number words
number sense
odd number
ordered numbers
ordered numbers
ordered pairs       
patterns
percent

perimeter     
place value
polygon
population
prime number
prime factor
probability
product
quadrant  
quotient 
ratio  
reflection   
rotation   
rounding    
side      
slide    
SI notation     
standard form         
tangram
translation     
turn  
volume  
whole number          
weight 
word problems

Here are some math glossaries online:

Harcourts School
math.com

addition (regrouping): we regroup when we have enough in one place value to move to another e.g. 7 ones plus 5 ones equals 12 ones or 1 tens and 2 ones. We often need to regroup when we are adding numbers together..........see lesson on traditional regrouping while adding; however, we also need to practice adding numbers together without stacking them (e.g. 505 + 411 = 916). This takes practice and understanding of the patterns in our number system, place value.

algorithm a precise step-by-step procedure for solving a problem (our goal is to limit our use of algorithms and help students try to create their own understanding of the concept e.g seeing the patterns in the 9 times facts rather than memorizing them)

area: the number of square units needed to cover a surface
         e.g. the area of a rectangle 2m by 6m takes 12 square meters to cover
         see using a factor chart to find the possible lengths and widths for a given area

base-ten language: we use words to describe each place value e.g. 104 one hundreds zero tens and four ones

broken-line graph: (also see broken-line graph)

chance: see probability

circle graph: a type of graph using data showing how the parts are related to the whole

circumference: the distance around a circle (also see circumference)

composite a whole number having more than two factors (math glossary) (also see composites) e.g. 4 has three factors: 1, 2, 4 (see example)
                   
conversions:

fraction - decimal - percentage
(also see converting visual )
     - these number forms can all represent the same number
     - for example 3/4 can be read as 3 ÷ 4
     - using a calculator we find that 3 ÷ 4 = 0.75
     - to find the % (the number out of 100), we need to multiply the decimal by 100
     - 0.75 as a percentage = 75 %
     - therefore, 3/4 = 0.75 = 75 %

units

coordinates: see ordered pairs

decimal: a number with digits to the right of the decimal point e.g. 5.48 (see adding or multiplying decimals). A decimal is another way to write a fraction and we read decimals so that the fraction is heard. For example, 5.48 is read "five and forty-eight hundredths). The 'and' tells the listened that there is a decimal point. For a lesson on decimals see decimals.

dividend: the number that is to be divided e.g. 35 ÷ 5 = 7 35 is the dividend

division: division is the result of dividing a large group (dividend) into smaller smaller groups (divisor); it is also the inverse of multiplication

see: division with a remainder and division with a decimal answer

divisor: the number that divides the dividend e.g. 35 ÷ 5 = 7 5 is the divisor

expanded notation: writing numbers out showing the place value of each digit e.g. 346 = 300 + 40 + 6

even: a number divisible by 2 (the one's place value contains an even number e.g. 2, 4, 6, 8 or 0

estimating: changing a exact number to an 'easy to use' number that is very close to the exact number
; we follow specific rules to do this. When rounding off a number we look at the digit just before it. If that digit is a 5 or greater, we increase the digit in our place value position by 1. If the digit is less than 5 we do not change it.
          a) rounding off to a specific place value e.g. rounding off 7 456 to the nearest hundreds = 7 500
          b) front-end rounding means we round off to the first (front) one or two digits e.g. 457 678 = 460 000

factor: a number that divides evenly into another number (also see factors, example)

flip: see reflection

fraction: a part of a whole e.g. 1 out of 3 children are playing hopscotch or 1/3 of the children

 

 

 

 

 

 

 


3 squares are green (numerator)
6 squares in all (denominator)

so, 3 out of 6 squares are green, or 3/6
- you can reduce this to 1/2



example: for another view, go to Harcourt Math Glossary

practice activity: go to www.rainforestmaths.com, choose your grade level, choose Fractions; or go to http://nlvm.usu.edu/en/nav/vlibrary.html

tutorial: go to www.learnalberta.ca (grade 5) for a couple of tutorials on fractions

frequency diagrams: (also see frequency diagrams)

height: the distance from the bottom (base) to the top of a figure or solid shape

intervals: (also see intervals)

irregular shapes: shapes that do not contain symmetry (also see irregular)

line plots: a 'picture' of data that shows the data along a number line (see line plot)

mass: see weight, a unit of weight e.g. the mass of the pumpkin was 3 kg

mental math: when you use what you know to solve a question in your head without the aid of a pencil and paper e.g. 7 X 8 =........ (4 X 8) + (3 X 8) = 32 + 24 = 56 (see strategies)

multiple: the set of numbers a specific number can go into evenly e.g. 20, 30, 40 are multiple of 10 (see multiples)

multiplication: the product (total number of items) of the number of equal groups e.g. we say 4 groups of 6 items = 24 items rather than 4 'times' 6 equals 24. The word 'group' means something whereas the word 'times' does not see multiplying large numbers using arrays, using step-by-step and the 'traditional' method

number: a symbol or combination of symbols representing a collection or quantity e.g. the number 15 represents a specific collection of apples. We need to be able to see that this number can be shown in many different ways e.g. 10 + 5, 3 X 5, 14 + 1, 30/2, (3 + 2) x 5, 20 - 5, (3 X 3) + (2 X 3)......

number patterns: an ordered set of numbers arranged according to a rule (see Maths Dictionary). For example a) 10, 8, 6, 4, 2, 0 (rule - 2), b) 10, 100, 1 000, 10 000, 100 000 (rule X 10)

number words: numbers written in word form e.g. ten (see Number Words for a printable page)

number sense: developing number sense is when the student understands a concept or process by being able to recognize the pattern, visualize the process, or recognize the concept in a new form as opposed to memorizing a rule or algorithm they have been taught.

odd: an odd number not divisible by 2 (one's place value contains an odd number e.g. 1, 3, 5, 7, 9

ordered numbers: number that appear in sequence either from greatest to least or least to greatest (also see practicing ordering numbers)

ordered pairs: ordered pairs are used to show where the x and y coordinates of a point are located on a plane (also see ordered pairs)

patterns: a number pattern is a constant or predictable relationship between quantities. For example, 1 X 10 = 10, 2 X 10 = 20, 3 X 10 = 30 the rule for the 10s facts is that the input (e.g. 3) increases the output previous output (2) by 10 each time .

percent: a number divided by 100 e.g.  40/100 = 40 % ; the ratio of a number to 100  e.g. 3/5 = 60/100 = 60%. Again, percent is another way to talk about a fraction, just like decimals represent fractions

perimeter: the distance around a shape (see perimeter)

place value: the value of a digit depends on where it is located, its place value e.g. 73629.57 the 6 is in the hundreds' place.

Millions
(family)

Thousands
(family)

Ones
(family)

Hundred Millions

Ten
Millions

One Millions

Hundred Thousands

Ten Thousands

One Thousands

Hundreds

Tens

Ones

Note: our number system is based on the pattern: 'families' containing ones, tens, hundreds. This makes is easier to predict the next section of numbers e.g. Billions contains One Billions, Ten Billions, Hundred Billions

another way to view this number to to identify each place value:

7 ten thousands 3 one thousands 6 hundreds

We can also regroup the number so that 556 can be regrouped in a variety of ways. For example:

5 hundreds 5 tens 6 ones = 556.....or

4 hundreds 15 tens 6 ones = 556.....or

2 hundreds 35 tens 6 ones = 556

Example: for a more detailed view go to Harcourt Math Glossary

Practice: go to www.rainforestmaths.com, choose your grade level > Numbers or go to http://nlvm.usu.edu/en/nav/vlibrary.html

Tutorial: go to www.learnalberta.ca > log in as a guest > Grade Five

polygon: a 2D shape formed by 3 or more lines e.g. rectangle, square, triangle (see polygon or geometric shapes)

population: the entire group considered in a survey e.g. 'all girls age 13 in the school' (also see population).

prime: a number divisible only by itself and 1 (see primes, example)

prime factor: a prime number that divides exactly into a given number is one of its prime factors (example)

probability: the chance that an event will happen shown as a ratio of the number of favourable outcomes over number of possible outcomes. For some practice, go to www.rainforestmaths.com, choose your grade and click on the 'Probability' section. (lesson)

product: the answer to a multiplication question (see product). The product of 6 X 3 is 18.

quadrant: (see quadrant)

quotient: the answer to a division question. The quotient of 18 ÷ 3 is 6. (see quotient)

ratio: the comparison of two numbers by division 2:5 or 2/5 (2 out of 5 counters are red)

reflection: the flipped picture or mirror image of a shape (see reflection)

rotation: the movement or the turning of a shape around a fixed point (see rotation)

side: the edge or line forming the border of a shape or object

slide: see translation

SI notation: international system of units e.g. cm = centimeters, g = grams

standard form: numbers written using digits e.g. 10

subtraction (regrouping): as with adding, we regroup or borrow when we do not have enough in one place value to take away what we need to ..... see lesson subtraction (regrouping) on traditional regrouping while subtracting; however, as with adding, we need to practice subtracting numbers without stacking them (e.g. 525 - 411 = 114). Once again, this takes practice and understanding of the patterns in our number system, place value.

tangram: a puzzle made of 7 polygon shapes

translation: the movement of a shape or figure along a straight line

turn: see rotation

volume: the number of square cubes needed to fill a surface  

e.g. the volume of rectangular prism (length = 12m by width = 5m  by height 2 m takes 120 cubic meters to fill

whole number: the numbers (including 0) you would use to count objects (therefore, whole numbers do not include fractions or decimals)

weight: mass, the mass is the amount in an object measured in e.g. kilograms, pounds etc

word problems (or problem solving): Sometimes our questions are in the form of a written word problem. To solve these, we often follow five steps:

1) read the question twice, 2) draw a picture showing what is happening in the problem, 3) write a number sentence show the problem, 4) solve the number sentence, 5) write a clearly written sentence describing the answer (remember to begin with a capital and end with a period). see example
It is also important to be able to create a word problem when given a solution e.g. 5 + 14 =

large numbers: here are some examples of larger numbers:

      407      four hundred six
  3 589    three thousand eighty-nine
24 654   twenty-four thousand six hundred four
* remember that we do no use the word 'and' unless we are talking about a decimal placement.

Here are some examples of decimal numbers. Remember that we "read" the decimal as "and".

3.5 = three and five tenths

14.74 = fourteen and seventy-five hundredths

 

 

The 'How Tos'

adding & subtracting decimals

The most important part about adding and subtracting with decimals is to ensure that your decimal points line up. You may add a zero to take a space if that helps:


e.g. 3.5 + 2.45 + 1.237 =

set up:

3.500
2.450
1.237
7.187

e.g. 22.88 - 1.6 =

set up:


22.88
- 1.60
21.28

* also lesson

 

Finding Area: You use the following formula when find the area of a square or a rectangle A = L x W

example: find the area of a rectangle with a length of 7 m and a width of 5 m

A = L x W
A = 7m x 5m
A = 36 sq m

Finding Perimeter: You use the following formula when find the perimeter of a polygon.

P = (sum of all sides)

example: find the perimeter of a rectangle with a length of 7 m and a width of 5 m

P = (sum of all sides)
P = 7m + 5m + 7m + 5m
P = 24 m

 

Factors, Multiples, Primes and Composites

Finding Factors:

1) method #1: this is a factor chart. You create two columns of numbers. On the left is a list of numbers you ask "does this number divide into the number you are finding factors for. You start with '1' and work up systematically. You stop when your next number also appears in the right-hand column.

e.g. Find the factors of 24

Does this number divide into 24?

Yes, how many times, or no.

1

24

2

12

3

8

4

6

5

no

6

4

Circle the factors (pairs e.g. 4 & 6) and then write them in sequence: 1, 2, 3, 4, 6, 8, 12, 24

The prime factors of 24 are 2 & 3 (by definition 1 is not a prime number)

 

Finding Multiples:

 

Finding Multiples:

Prime Factoring:

1) method #1: You will create a factoring tree to find the prime factors for a number.

e.g.  Find the prime factors of 24 using a factoring tree. (for another example see math glossary)

  24

                              /      \
                           2        12
                         /           /    \
                       2          2      6 
                      /           /       /   \
                    2          2       2    3       

The prime factors of 24 are 2 and 3.

Since you cannot break the numbers down any smaller, these are the prime factors of 24.
(Remember, 1 is not prime number.)

2) method #2: starting with dividing by 2, develop a list of factors

                       2  I24 
                       2  I12   
                       2     I6 
                               3       2 X 2 X 2 X 3 = 24    so, the prime factors of 24 are 2 and 3                       

Finding Composites:
1) method #1: You create a chart to find whether a whole number has two or more factors:

Whole Number

Factors

1

1

2

1, 2

3

1, 3

4*

1, 2, 4

5

1, 5

6*

1, 2, 3, 6

7

1, 7


4 & 6 are composite numbers, 1, 2, 3, 5, and 7 are not

Mental Math strategies

1.    skip counting:    8 X 2 = 2, 4, 6, 8, 10, 12, 14, 16

2.    commutative property   9 X 2 = 2 X 9

3.    doubling:    2 X 8 = (8 + 8) = 16

4.    repeated doubling:  4 X 5 = (5 + 5) + 10 = 20

5.    distributive property: 4 X 15 = 4 X (10 + 5) = (4 X 10) + (4 X 5) = 60

6.    halving: 12 ÷  2 = 1/2 of 12 = 6

7.    repeated halving: 16 ÷  4 = 1/2 of 16 = 8           1/2 of 8 = 4 

8.    associative property  (3 X 5) X 2 = 3 X (5 X 2)

9.    annexing then adding zero 62 X 10 = 62 X 1 and add a 0         

 

Multiplying Large Numbers

a) Using arrays or grid paper to break a question down into smaller parts.

- here is an easy one just to prove that it works

12 X 12 = 144

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



10 X 10 = 100
    2 X 10 = 20
    10 X 2 = 20
      2 X 2 =   4
                 144

The arrays help us break large numbers down into smaller, easier to solve sections.




now, with a large number
e.g. fine the product for 12 X 36

grid paper 12 X 36

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


This paper can be broken down into smaller groups
e.g.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


The purple, yellow, and pink sections are all   10 X 10 = 100 sections, so 3 X 100 = 300
The white section is 6 X 10 ........................................................................ so 6 X  10  =   60
The brown, red, and dark green sections are all  2 X 10 = 20, so............... 3  X  20 =   60
Finally, the last little section is ..........................................................................2  X  6   =   12

If we add all of these products up, we solve the larger equation.................................... 432

So, 12 X 36 = 432

b) Using expanded notion to multiply large numbers

method #1  Now we can use expanded notation to help us "see" the series of steps. We call this the 'step by step' method.

method #2  This is the traditional method where we 'carry' numbers to show our regrouping.                           

                                      

                                                             

example
                            
      12        (10 + 2)
X   12         (10 + 2)            
        4          (2 X 2)
      20        (2 X 10)
      20        (10 X 2)
    100      (10 X 10)
    144

example                                   

    12     
X   12 
 
     2 4
    120       
   144                                                

example

    12      (10 + 2)
X 36 
     (30 + 6)
    12       (6 X 2)
    60     (6 X 10)
    60     (30 X 2)
  300   (30 X 10)
  432

 example
    1
    12     
X  36 
   
    72 
  360 
  432

 example
    38      (30 + 8)
X 24
     (20 + 4)
    32       (4 X 8)
  120     (4 X 30)
  160     (20 X 8)
  600   (20 X 30)
  912

example
  13
     38     
X   24
    
   152 
   760
   912                                         

 

Applying the process to problem solving. To use with Power of Ten, section 4, page 26
Building a Patio

You have 168 1 metre square patio blocks.
You must arrange into a rectangular shape.
Maximum length is 20 metres.
Use base-ten blocks or paper (e.g. graph paper) to plan your patio.

In pairs, students create diverse ways to generate solutions. They share their strategies, present, and support their suggestions. List strategies used e.g. multiplication facts, division, scale diagrams.

solution
12 X 14 = 168

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 




Making Connections #1 to Factors and Prime Factors
 
        Factor Chart                                       Factor Tree

      168                                                      168
  1            168                                          /          \
  2              84                                        2           84
  3              56                                       /           /     \
  4              42                                     2         2       42
  5              no                                    /          /         /    \
  6              28                                  2         2      2      21
  7              24                                 /          /        /       /    \
  8              21                               2         2       2      3     7
  9              no
10              no
11              no
12              14
13              no
14

 

Using the factor tree, we find that the prime factors of 168 are  2  2   2   3   7  so 2 x 2 x 2 x 3 x 7 = 168

Other factors can also be found using the 'cover-up' method.

- cover one 2 and the remaining factors visible are2 x 2 x 3 x 7 which =  84, thus 2 x 84 = 168
- try other 'cover-ups'

 

We can use a Factor Chart to find rectangles for a given area.
For example, using the above chart. We know that length X width = the area of a rectangle.

If the area is 168 square units, then all of our factor pairs (1, 168; 2, 84) provide the possible dimensions for this area. The area of a rectangle 6m  by 28m is 168 square meters. The following is a list of possible rectangular shapes for the area of 168 square meters. (You may want to check it out using graph paper.


1m  by 168m
2m  by  84m

3m  by  56m
4m  by   42m
6m  by   28m
7m  by   24m
8m  by   21m
12m by 14m


From this information, we know that 12m X 14m is the only rectangle that will give us a shape that has no side longer than 20m. Thus, the answer to our patio question, completed quickly and efficiently.

For more practice, go to graph paper and scroll down to find a variety of square areas you can use. For example, cut out the 25 square array and arrange them into as many rectangular shapes as your can. Record these dimensions. Create a Factor Chart, or T-table, and see how many you found.

Making Connections #2
to divisors

Use the Factor Chart to list all of the divisors:
e.g.   2 x 84            168 ÷ 2 = 84
                                168 ÷ 84 = 2


or........

Use the 'cover-up' method to list all of the divisors:

e.g.  2 x 84          (2)x (2 x 2 x 3 x 7)

168÷ 2 = 84
168 ÷ 84 = 2

So, 12 X 14 = 168 is the only patio solution because any other rectangular shape has a side of more than 20.
Other rectangular shapes that do not fit the criteria include

1 x 168
2 x 84
3 x 56
4 x 42
6 x 28
8 x 21
12 x 14 ............ the only possible solution


Multiplying Decimals
We solve multiplication questions the same, whether there are decimals or not. The only difference arises when we are finished the multiplication part. We then go back to the question, count the number of digits on the right side of a decimal and then count in that many digits in our answer.

   1
    12     
X 36    
    72 
  360 
  432

  1
    1.2      there are 2 digits to right of decimals
X 3.6    
    72 
  360 
 4.32      so, we need to count in two digits to place the decimal

* see lesson on multiplying decimals

Dividing Large Numbers
a) Using arrays or grid paper to break a question down into smaller parts. Using the original array, we divide 144 ÷ 12 = 12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



144 squares divided into strips of 12 makes 12 strips.
                                                                                                                                                                                              
b) Division questions can be written several ways.
                                                                                                                                                                
When we have a remainder, we can show our answer in a couple of ways. For example, we show the answer to the following question in two ways:      147 ÷ 12 =          a) 12 R3 , or b) 12.25     (we will round off to the nearest hundredths)
Look at the following examples:

method #1  This is the traditional way we solve long division questions. When we have a remainder, we write the answer in this way   12 R3

method #2  Although we solve long division questions the same way as the traditional process, if we want to provide an answer in decimal form when we have a remainder, then we need to keep dividing bringing down more zeros, in these cases three zeros so that we can round our answer off to the nearest hundredths.

 
           _012____
       12)147       
           -120      
               27      
               24    
                 3    


answer = 12 R3


             012.250____
       12)147.000
             12
               27
               24
                 30
                 24
                    60
                    60
                       0

answer = 12.25

example 

             012  R3
       36)435      
           - 360       
               75         
               72 
                 3       


answer = 14 R31



             012.083 
       36)435.000
             36 
               75       
               72    
                 300
                 288
                   120
                   108
                      12*
* this is not a remainder, it just gives us enough digits after the decimal to round off

answer: 14.08







Converting from
Fraction to Decimal to Percentage

Using visuals helps students understand that these are different forms describing the same number. 

 

 

 

 

 

 

 

 

 

 


This shape has ten equal parts. One part out of the ten parts is pink. Therefore, 1/10 of the shape is pink.
                                                                                                                                      
Using decimals, we need to remember that the first place value after the decimal point is the tenths place. One tenth of this picture is pink. Therefore, we write 0.1 of this picture is pink.

Using percent, we want to know how many parts would be pink if this were a shape made up of 100 parts. To do this, we need to multiply the fraction by 10/10 or 1 so that we know how many parts would be pink if there were 100 parts in all. We need to keep the same ratio. 1/10 X 10/10 = 10/100 therefore, 10 squares need to pink. Ten out of the 100 parts are pink and, therefore, 10% of the shape is pink.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



Converting the decimal to percentage means we multiply the decimal by 100. So, 0.1 X 100 = 10.0, or 10 %. Later, we just move the decimal over to the right two spots knowing that this is the result of multiply a decimal by 100.

Our conversions look like this:    1/10   =  0.1  = 10%         
Other examples,    1/4   = 0.25  = 25 %
                                 1/2  = 0.50  = 50%


Graphing T-tables: Student first fill in any missing data. They then take the data under each heading (Input, Output) and graph it. The Input data is recorded along the bottom of the graph while the Output data is recorded along the side of the graph.

  Input 

Output

1

2

2

4

3

6

4

8

5

10

6

 

7

 

8

 

 

 

 

 

Weekly Graphs:
              teacher template for overhead

student template for working with graph data


Word Problems: To solve written word problems we often follow five steps:
1) read twice, 2) draw a helpful picture, 3) write a number sentence, 4) solve the number sentence, 5) write a clearly written sentence describing the answer


Example #1
Mike ran 5 miles one day and 7 miles the next day. How many miles did
Mike run over the two days?
day one:........5 miles

day two:........7 miles

5 + 7 = 12

Mike ran 12 miles over the two days.
 * Be sure that you answer the question in a full sentence using key words in the question.

Example #2
A dog ran 1.25 km in a minute.
At this pace, how far did he run in 12 minutes?
I.............I.............I.............I............I..............I.............I............I............I..............I............I...........I.............I


1.25 km

1.25
X.12
250

At this pace, the dog ran 15 km in 12 minutes.





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