1. Adding and Subtracting Decimals
COURSE 2 LESSON 1-2
Find
Estimate , or 27
Align the decimal points.
2.150
7.632
26.282
Insert zeros so each addend has the same number of decimal places.
Check for Reasonableness is reasonable since it is close to 27.
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2. Adding and Subtracting Decimals
COURSE 2 LESSON 1-2
You have 5.08 min left on a CD. How much time will you have left after you record a 2.5 minute song?
Regroup. 10 4
5.08
– 2.50
2.58
You will have 2.58 min left on the CD.
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3. Adding and Subtracting Decimals
COURSE 2 LESSON 1-2
You guess that the weight of a package is 10 lb. At the post office, the scale shows that the actual weight is 7.6 lb. Find the difference between your guess and the actual weight.
Insert a decimal point and one zero.
10.0
– 7.6
Regroup.
10.0
– 7.6 9 10
Subtract.
10.0
– 7.6
2.4 9 10
Your guess is 2.4 lb more than the actual weight.
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