Math Unit 2 Review for the Test

Math Unit 2 Review

This is only a test!

(5x1 + 3x1/10 + 8x1/100 +7x1/1000)

6.543

0.024

3.98



Rounding

• Identify the place you are rounding to, and place a
box around it.

• Check the digit to the right. If it is greater than or
equal to 5, then the number in the box increases by
one. If it is less than 5, then the number in the box
stays the same.

• Keep everything before the box. Everything after the
box becomes zero. If the zeroes come at the end of a
decimal, they can be dropped.

Example : Round 13.56 to the nearest
tenths place.

13.56 __1 _3_ . _6_ _0_

13.6 is the answer.

Rounding Decimals

Rounding Decimals

Rounding Decimals

Mrs. Willard is making a strawberry cake to share with his
class. She went to the story to buy strawberries and
calculated the costs.
Cake recipe:
• 2.14 pounds of strawberries
• Cost per pound $0.91
• Calculation : 2.14 x $0.91 =1.9474
Find the actual cost by rounding to the nearest hundredths.

Adding and Subtracting

The Basic Steps:

• Line up the numbers by the decimal point.
• Fill in missing places with zeroes.
• Add or subtract.

Example

Mr. Leader rides his bike 400 meters in 14.45
seconds. Later that day he rode his bike another
400 meters in 12.89 seconds

How long did it take Mr. Leader to bike 800
meters in seconds?

Mr. Leader rides his bike 600 meters in 32.45
seconds. Later that day he rode his bike another
600 meters in 30.76 seconds

How long did it take Mr. Leader to bike 1,200
meters in seconds?

David runs 1 mile to the bus stop. He has
already ran .42 miles.

How much farther does he have to run?

Riley runs 1 mile to the bus stop. She has
already ran .27 miles.

How much farther does she have to run?

Multiply Decimals:

• You do not line up the factors by the decimal.
• Instead, place the number with more digits on top.
• Line up the other number underneath, at the right.
• Multiply
• Make a t-chart to record how many numbers are

behind the decimal point.
• Count the number of decimal places (from the right)

in each factor.
• Use the total number of decimal places in your two

factors to place the decimal in your product.

Example: 5.63 x 3.7

1 2
42 1

5.63
x 3.7

11

1 39 4 1
+ 16890

20.8 31 3

• Mrs. Chicken makes 4 dollars an hour at her
job. If she worked 3.5 hours how much did she
make?

Try This: 6.5 x 15.3

15.3
x 6.5
+

Dividing Decimals

Dividing Decimals with Models

Dividing Decimals

WATCH
https://www.youtube.com/watch?v=py

Qf8uaSirw

Add and Subtract Factions

• List the multiples of both denominators.
• Find the least common multiple (LCM).
• Write new fractions with the LCM as the new

denominator.
• Find the factor you multiply by to get from your

original denominator to your new denominator.
• Use that same factor, and multiply it by your

original numerator to get a new numerator.

WHAT DOES THAT MEAN?

Let’s illustrate the steps with an
example.

3 +1
46

3+ 1
4 6

x3 9 2 x2
12 12
+
11
Multiples of 4: 4, 8, 12, 16, 20 12
Multiples of 6: 6, 12, 18, 24, 30

Example 2

9 2 10, 20, 30, 40, 50
5 5, 10, 15, 20, 25
10
4 x2 5
x1 10
= 10
9 1
10 = 2



Add and Subtract Mixed Numbers and
Improper Fractions

• Method 1

https://www.youtube.com/watch?v=LMAOcfhvrYo&feature=youtu.be

• Method 2

https://www.youtube.com/watch?v=X-ebopde6YY&feature=youtu.be