1. Multiplying Decimals
Notes for August 25th

2. IWBAT multiply decimals.
Today’s Objective
IWBAT multiply decimals.

3. If you have been in intervention with me, use the box method.
Warm-Up
Yes let’s warm-up because I am cold!!!
2 x 457 =
14 x 3 =
104 x 6 =
45 x 97 =
If you have been in intervention with me, use the box method.

4. Why is multiplying decimals important?
In case you need to answer this question.
The iPhone weighs 4.83 ounces. Alondra orders it online from apple.com. If costs $0.25 per ounce to ship a package, how much will shipping cost Alondra?

5. Check out these problems…
iTunes is selling songs for $0.25 each. If you buy 4 songs, how much will it cost you?
It costs $2.50 per minute to call Japan. If you talk for 4 minutes, how much will it cost you?
Text messages cost $0.50 each. If you send 5 messages, how much is your bill?

6. Steps to multiplying decimals
Set up the problem like a
normal multiplication problem.
Don’t line up the decimal! Pretend it’s not there…
Multiply like normal!!
Count the number of numbers behind the decimal in your original problem.
Starting on the right side of your answer, move the decimal over that many times.

7. Fingers!
Hold the number of fingers to represent how many times you move the decimal.

8. How many times will you move the decimal in your final answer?1)
0.03 x 4)
0.05 x 231 2)
2.6 x 0.08 5)
0.02 x 4.67 3)
5 x 0.445 6)
3.2 x 5.8

9. Steps to multiplying decimals2 1
0.55 x 1.3 1
Set up the problem like a
normal multiplication problem.
Don’t line up the decimal! Pretend it’s not there…
Multiply like normal!!
Count the number of numbers behind the decimal in your original problem.
Starting on the right side of your answer, move the decimal over that many times. 55 13 x 1 16 5 5 5 + 7 1 5 3
715

10. Steps to multiplying decimals2 2
0.25 x 0.53 1 2
Set up the problem like a
normal multiplication problem.
Don’t line up the decimal! Pretend it’s not there…
Multiply like normal!!
Count the number of numbers behind the decimal in your original problem.
Starting on the right side of your answer, move the decimal over that many times. 25 53 x 7 5 1 12 5 + 1 3 2 5 4
1325

11. 1)
0.03 x 4)
0.05 x 231 2)
2.6 x 0.08 5)
0.02 x 4.67
1) ; 2) .208; 3) 2.225; 4) 11.55; 5) .0934; 6) 18.56 3)
5 x 0.445 6)
3.2 x 5.8