# Add and subtract decimals - practice problems

This lesson contains a variety of exercises for adding and subtracting decimals with up to two decimal digits, meant for fourth or fifth grade.

1. Add some hundredths so that the next whole tenth is filled.

 a. 0.47  +  0.03 = 0.50   b. 0.55  +    c. 0.36  + d. 0.06  + e. 0.32  + f.  0.97  + g. 0.28  + h. 3.13  + i.  3.99  +

2. Find the missing numbers.

 + 0.05 + 0.08 + 0.06 + 0.02 + 0.04 + 0.01 + 0.09 + 0.05 a.  0.05

___

___

___ ___ ___ ___ ___ 0.45

 – 0.06 – 0.08 – 0.1 – 0.04 – 0.2 – 0.07 – 0.02 – 0.03 b.  8.28

___

___

___ ___ ___ ___ ___ 7.68

 – – – – – – – – c.  2.55

2.53

2.5

2.43 2.38 2.34 2.29 2.15 2

3. Subtract mentally. Pay close attention to the numbers that only have tenths. Tag a zero to them
so that the addends will have the same amount of decimals.

 a.  0.4  –  0.06  = f.  0.34  –  0.2  = k.  0.44  –  0.1  = b.  0.6  –  0.05  = g.  0.6  –  0.2  = l.  1.32  –  0.02  = c.  0.8  –  0.02  = h.  1.1  –  0.06  = m.  0.14  –  0.1  = d.  1.5  –  0.01  = i.   0.82  –  0.02  = n.  1.23  –  0.2  = e.  0.3  –  0.15  = j.  0.73  –  0.5  = o.  1.77  –  0.3  =

4. Now add and subtract both!

 – 0.03 + 0.07 – 0.09 + 0.08 – 0.1 + 0.11 – 0.08 + 0.04 0.5

___

___

___ ___ ___ ___ ___` 0.5

5. Figure out what was done in each step - either addition or subtraction!        2.2

2.25

2.35

2.09 2.1 2.17 2.2 2.02 2

6. Write the following addition/subtraction sentences using decimal numbers, and solve.

 a. 5 100 + 24 100

0.05 + 0.24 = _________

 f. 1 7 10 + 6 100
 k. 2 53 100 – 3 10
 b. 5 10 + 21 100

 g. 3 78 100 – 4 100
 l. 12 4 10 – 9 33 100
 c. 75 100 – 25 100

 h. 1 6 10 – 8 100
 m. 52 100 + 1 7 100
 d. 5 10 – 21 100

 i. 4 45 100 + 3 100
 n. 99 100 + 1 1 10
 e. 1 17 100 + 2 7 100

 j. 12 4 100 + 10 3 10
 o. 1 47 100 – 1 7 100

This lesson is taken from Maria Miller's book Math Mammoth Decimals 1, and posted at www.HomeschoolMath.net with permission from the author. Copyright © Maria Miller.

#### Math Mammoth Decimals 1

A self-teaching worktext for 4th grade that gives a solid foundation for decimals. It covers tenths and hundredths, comparing decimals, adding and subtracting decimals both mentally and in columns, multiplying decimals by whole numbers, rounding, estimating, and money problems.

Download (\$3.50). Also available as a printed copy.

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