1. Rounding Decimals Review and Multiplying Decimals

2. ___ , ___ ___ ___ ___ ___ ___ ___
Naming Decimals
Decimals are read as “and”
___ , ___ ___ ___ ___ ___ ___ ___
Thousandths
Thousands
Ones
Hundredths
Hundreds
Tens
Tenths
Ten Thousandths
Read as 518 and 21 hundredths

3. Rounding Review Find the number. Circle it. Look next door.
4 or less just ignore.
5 or more add one more.
Example: Round 5368 to nearest hundreds.
Circle the 3 in the hundreds place.
Look next door at the 6.
It is 5 or more so add 1 more to the hundreds place.
5368 rounds to 5400

4. Rounding Review 2.876 31.6999 2.9 31.70 Round to the nearest tenths
Round to the nearest hundredths
2.876
2.9
31.70

5. Rounding Review 3.478 22.5972 3.5 22.60 Round to the nearest tenths
Round to the nearest hundredths
3.478
3.5
22.60

6. Multiplying Decimals
Steps for Multiplying Decimals
Step 1: Write the problem vertically.
Step 2: Ignore the decimal point(s) and multiply.
Step 3: Determine where the decimal point goes in the product.
Place the decimal point in the answer by counting how many places the decimal point has moved.

7. Multiplying Decimals
Multiply 3 x 0.14 =
0.42
0.14
3 x 0.14

8. Multiplying Decimals Multiply 3 x 0.14 0.42
Step 1: Write the problem vertically
0.14 x
Step 2: Ignore the decimal points and multiply 4 2
Step 3: Determine where the decimal
point goes in the product.
0.42
The decimal moves two places to the left

9. Multiplying Decimals Multiply 5 x 0.18 0.90 5 x 0.18 0.18 = 1whole

10. Multiplying Decimals Multiply 5 x 0.18 0.904
Step 1: Write the problem vertically
0.18 x
Step 2: Ignore the decimal points and multiply 9
Step 3: Determine where the decimal
point goes in the product.
0.90
The decimal moves two places to the left

11. Multiplying Decimals
Multiply 0.2 x 0.6 =
0.2
0.6
0.2

12. Multiplying Decimals
Multiply 0.2 x 0.6 =
0.2
x 0.6
0.6
0.2

13. Multiplying Decimals
Multiply 0.2 x 0.6 =
0.2 x 0.6
0.6
0.2
= 0.12

14. Multiplying Decimals Multiply 0.2 x 0.6 0. 12
Step 1: Write the problem vertically
0.2
x 0.6
Step 2: Ignore the decimal points and multiply 1 2
Step 3: Determine where the decimal
point goes in the product.
0. 12
The decimal moves two places to the left

15. Multiplying Decimals
Multiply 0.4 x 0.7 =
0.4
0.7
0.4

16. Multiplying Decimals
Multiply 0.4 x 0.7 =
0.7
0.4
0.4
x 0.7

17. copyright©amberpasillas2010
Multiplying Decimals
Multiply 0.4 x 0.7 =
0.7
0.28
0.4
copyright©amberpasillas2010

18. Multiplying Decimals Multiply 0.4 x 0.7 0. 28
Step 1: Write the problem vertically
0.4
x 0.7
Step 2: Ignore the decimal points and multiply 2 8
Step 3: Determine where the decimal
point goes in the product.
0. 28
The decimal moves two places to the left

19. . 200 x . 25 1 + 4 5000 Multiplying Decimals
Move the decimal two places
to the left in your answer.
x . 25 1 + 4 .
5000

20. Multiplying Decimals HOW MANY DECIMAL PLACES? 1) 3.1(0.28) 3.1
2 decimal places
0.868
1 + 2 = 3 decimal places
2) (0.4)(2.53)
0.4
1 decimal place
 2.53
2 decimal places
1.012
1 + 2 = 3 decimal places

21. Multiplying Decimals 1 2 1 1 0.16 x 30 70 x 1.2 0.0048 x 32 1 4 9 6 41) 1
0.16
x 30 2) 70
x 1.2 3)
0.0048
x 32 1 4 1 9 6 4 8 + 7 1 4 4 4 8 8 4 1 5 3 6

22. 3 Evaluate The Power 4 An exponent tells how many times a
number is multiplied by itself. 4 3
Exponent
Base 4
3 is written as 3 • 3 • 3 • 3 = 81
This exponent is read three to the fourth power.

23. Evaluate The Power Evaluate (0.2)2 0. 04 This means (0.2)(0.2) 0.2
x 0.2 4
0. 04
The decimal goes moves two places to the left

24. Calculate Area With Decimals
Area = base x height
0.58 in.
Multiply 4 x 0.58
4 in. 3 2
The decimal moves two places to the left.
0.58 x
Area is square units! 2 3 2
2.32 in2

25. Review

26. Multiplying Decimals Multiply 0.4 x 0.14 0.056#5
Multiply 0.4 x 0.14 1
0.14 x
Step 1: Write the problem vertically
Step 2: Ignore the decimal points and multiply 5 6
Step 3: Determine where the decimal
point goes in the product.
0.056
The decimal moves 3 places to the left.

27. The decimal moves two places to the left.#6
Evaluate (0.5)2
This means (0.5)(0.5) 2
0.5
x 0.5
The decimal moves two places to the left. 2 5
0. 25

28. Calculate Area With Decimals
# 7
Calculate Area With Decimals
The Area (A) is the number of square units needed to cover a figure.
0.98 in
Area = base x height
2 in.
Multiply 2 x 0.98 1 1
The decimal moves two places to the left.
0.98 x 1 9 6
Area is square units!
1.96 in2