Decimals

By the end of this unit, you will be able to:

A2 Represent decimals to thousandths
B1 Compute products of whole numbers and decimals
B2 Model and calculate the products of two decimal amounts
B3 Compute quotients of whole numbers and decimals
B4 Model and calculate the quotients of decimals divided by decimals
B9 Solve and create relevant addition, subtraction, multiplication and division problems involving decimals
B10 Estimate products and quotients involving whole numbers and decimals & decimals only


What is a Decimal?  Spy Guys


Decimal Place Value

Decimals are identified by the 'ths' at the end of the unit.

_______    _____   _____  .  ________  _________   _________

Hundreds - Tens - Ones - AND - Tenths - Hundredths - Thousandths



Decimal Place Value Game 

Materials:  Deck of Cards, Paper, Pencil (J/Q/K = 0, Ace=1), OR multisided dice (0-9)
Goal: Try to make the largest/smallest number possible

Take turns picking a card/rolling dice, individually decide where to place the number on your place value sheet trying to make the largest/smallest number possible.

____ ____ ____ . ____ ____ ____


Comparing and Ordering Decimals 

Start by writing one decimal beneath the other in their original order. 
6.01
0
0.601
6.1
0

Next, examine each decimal, write one or more zeros to the right of the last digit, so that all decimals have the same number of decimal digits.
6.010
0.601
6.100

Compare two decimals at a time.
6.010
0.601
6.100

From least to greatest:   0.6010,  6.010,  6.100

                                         

Ascending smallest first                    Decending = largest first

Least - Greatest                                   Greatest - Least


Adding & Subtracting Decimals

If you know how to add and subtract whole numbers, then you can add and subtract decimals.  Just be sure to line up the terms so that all the decimal points are in a vertical line.  Remember the snowman!

                                       


Multiplying Decimals

Multiply the numbers just as if they were whole numbers. Do not align the decimal points.

Place the decimal point in the answer by starting at the right and moving a number of places equal to the sum of the decimal places in both numbers multiplied.

Dividing Decimals

Put decimal point directly above decimal point in the dividend, divide as with whole numbers. 
Keep dividing until the answer terminates or repeats.

If the divisor is not a whole number, move decimal point to right to make it a whole number and move decimal point in dividend the same number of places. 

Check your answer: multiply quotient by divisor, does it equal the dividend? 


QUICK RECALL

Adding & Subtracting: remember the snowman buttons… line up decimals

Multiplying: m = boing, boing... bounce decimal over

Dividing:= move decimal up

Ordering & Comparing:  line up the decimals, fill in any missing zero's, compare one place value at a time looking for the largest/smallest and order accordingly.


Problem solving with Decimals  Spy Guys

Try it!


decimal cartoon

Kowalyk 2013