Computing with Decimals. Adding and Subtracting Decimals

Computing with Decimals

Adding and Subtracting

Decimals

Line up the decimal points.

4.6 + 7.23

Line up the decimal points.

4.6 + 7.23

4.60+ 7.23

Fill in with zeros.

4.6 + 7.23

4.60+ 7.23

Fill in with zeros.

4.6 + 7.23

4.60+ 7.23

Add or subtract normally.

4.6 + 7.23

4.60+ 7.23

Add or subtract normally.

4.6 + 7.23

4.60+ 7.2311 83

Place the decimal point under the other decimal points.

4.6 + 7.23

4.60+ 7.2311 83

Place the decimal point under the other decimal points.

4.6 + 7.23

4.60+ 7.2311.83

Line up the decimal points.

12 − 2.46

Line up the decimal points.

12 − 2.46

12 has a decimal point hidden behind it.

Line up the decimal points.

12 − 2.46

12.00− 2.46

Fill in with zeros.

12 − 2.46

12.00− 2.46

Fill in with zeros.

12 − 2.46

12.00− 2.46

Add or subtract normally.

12 − 2.46

12.00− 2.46

Add or subtract normally.

12 − 2.46

12.00− 2.46

9 54

Place the decimal point under the other decimal points.

12 − 2.46

12.00− 2.46

9 54

Place the decimal point under the other decimal points.

12 − 2.46

12.00− 2.46

9.54

Line up the decimal points.

15.2 − 7.93

Line up the decimal points.

15.2 − 7.93

15.20−7.93

Fill in with zeros.

15.2 − 7.93

15.20−7.93

Fill in with zeros.

15.2 − 7.93

15.20−7.93

Add or subtract normally

15.2 − 7.93

15.20−7.93

Add or subtract normally

15.2 − 7.93

15.20−7.93

7 27

Place the decimal point under the other decimal points.

15.2 − 7.93

15.20−7.93

7 27

Place the decimal point under the other decimal points.

15.2 − 7.93

15.20−7.93

7.27

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

24.5 – 13

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

16.8 + 4.72

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

143.2 + 4.18

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

35 – 4.5

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

2.14 + 8.4

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

9 – 3.65

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

4.02 + 0.75

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

8.4 – 2.13

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

5 + 0.52

Line up the decimal points.

Fill in with zeros. Add or subtract

normally. Place the decimal

point under the other decimal points.

12 – 0.68

Multiplying Decimals

Remove any extra zeros.

0.54 x 1.20 .54 x 1.2

0.064 x 2.09 .064 x 2.09

340 x 0.50 340 x .5

4.03 x 6.30 4.03 x 6.3

Remove any extra zeros.

0.70 x 2.05 .7 x 2.05

0.003 x 1.10 .003 x 1.1

500 x 2.70 500 x 2.7

0.082 x 0.09 .082 x 0.09

Find the number that has the most digits NOT INCLUDING zeros on the front.

.54 x 1.2

2 digits 2 digits

Find the number that has the most digits NOT INCLUDING zeros on the front.

.064 x 2.09

2 digits 3 digits

Find the number that has the most digits NOT INCLUDING zeros on the front.

340 x .5

3 digits 1 digit

Find the number that has the most digits NOT INCLUDING zeros on the front.

4.03 x 6.3

3 digits 2 digits

Find the number that has the most digits NOT INCLUDING zeros on the front.

.7 x 2.05

1 digit 3 digits

Find the number that has the most digits NOT INCLUDING zeros on the front.

.003 x 1.1

1 digit 2 digits

Find the number that has the most digits NOT INCLUDING zeros on the front.

500 x 2.7

3 digits 2 digits

Remove any extra zeros.

0.47 x 0.2

Remove any extra zeros.

0.47 x 0.2

Find the number that has the most digits NOT INCLUDING zeros on the front.

0.47 x 0.2

Find the number that has the most digits NOT INCLUDING zeros on the front.

0.47 x 0.2

2 digits

Find the number that has the most digits NOT INCLUDING zeros on the front.

0.47 x 0.2

2 digits 1 digit

Put that number on top lining up the right side of the problem.

0.47 x 0.2

2 digits 1 digit

Put that number on top lining up the right side of the problem.

.4 7x .2

Multiply normally.

.4 7x .2

Multiply normally.

.4 7x .29 4

Count the total number of decimal places in the problem.

.4 7x .29 4

Count the total number of decimal places in the problem.

.4 7x .29 4

2 decimal places

Count the total number of decimal places in the problem.

.4 7x .29 4

2 decimal places

+1 decimal place

Count the total number of decimal places in the problem.

.4 7x .29 4

2 decimal places

+1 decimal place3 decimal places

Put that many decimal places in the answer.

.4 7x .29 4

2 decimal places

+1 decimal place3 decimal places

Put that many decimal places in the answer.

.4 7x .29 4

2 decimal places

+1 decimal place3 decimal places

1 decimal place

Put that many decimal places in the answer.

.4 7x .29 4

2 decimal places

+1 decimal place3 decimal places

2 decimal places

Put that many decimal places in the answer.

.4 7x .2

.0 9 4

2 decimal places

+1 decimal place3 decimal places

3 decimal places

Put that many decimal places in the answer.

.4 7x .2

.0 9 4

Remove any extra zeros.

3.45 x 0.004

Remove any extra zeros.

3.45 x 0.004

Find the number that has the most digits NOT INCLUDING zeros on the front.

3.45 x 0.004

Find the number that has the most digits NOT INCLUDING zeros on the front.

3.45 x 0.004

3 digits

Find the number that has the most digits NOT INCLUDING zeros on the front.

3.45 x 0.004

3 digits 1 digit

Put that number on top lining up the right side of the problem.

3.45 x 0.004

3 digits 1 digit

Put that number on top lining up the right side of the problem.

3 . 4 5x . 0 0 4

Multiply normally.

3 . 4 5x . 0 0 4

Multiply normally.

3 . 4 5x . 0 0 41 3 8 0

Count the total number of decimal places in the problem.

3 . 4 5x . 0 0 41 3 8 0

Count the total number of decimal places in the problem.

3 . 4 5x . 0 0 41 3 8 0

2 decimal places

Count the total number of decimal places in the problem.

3 . 4 5x . 0 0 41 3 8 0

2 decimal places

+3 decimal places

Count the total number of decimal places in the problem.

3 . 4 5x . 0 0 41 3 8 0

2 decimal places

+3 decimal places5 decimal places

Put that many decimal places in the answer.

3 . 4 5x . 0 0 41 3 8 0

2 decimal places

+3 decimal places5 decimal places

Put that many decimal places in the answer.

3 . 4 5x . 0 0 41 3 8 0

2 decimal places

+3 decimal places5 decimal places

1 decimal place

Put that many decimal places in the answer.

3 . 4 5x . 0 0 41 3 8 0

2 decimal places

+3 decimal places5 decimal places

2 decimal places

Put that many decimal places in the answer.

3 . 4 5x . 0 0 41 3 8 0

2 decimal places

+3 decimal place5 decimal places

3 decimal places

Put that many decimal places in the answer.

3 . 4 5x . 0 0 41 3 8 0

2 decimal places

+3 decimal place5 decimal places

4 decimal places

Put that many decimal places in the answer.

3 . 4 5x . 0 0 4

.0 1 3 8 0

2 decimal places

+3 decimal place5 decimal places

5 decimal places

Put that many decimal places in the answer.

3 . 4 5x . 0 0 4

. 0 1 3 8 0

Remove any extra zeros.

3.40 x 1.98

Remove any extra zeros.

3.40 x 1.98

Find the number that has the most digits NOT INCLUDING zeros on the front.

3.40 x 1.98

Find the number that has the most digits NOT INCLUDING zeros on the front.

3.40 x 1.98

2 digits

Find the number that has the most digits NOT INCLUDING zeros on the front.

3.40 x 1.98

2 digits 3 digits

Put that number on top lining up the right side of the problem.

3.40 x 1.98

2 digits 3 digits

Put that number on top lining up the right side of the problem.

1 . 9 8x 3 . 4

Multiply normally.

1 . 9 8x 3 . 4

Multiply normally.

1 . 9 8x 3 . 47 9 2

Multiply normally.

1 . 9 8x 3 . 47 9 2

5 9 4 0

Multiply normally.

1 . 9 8x 3 . 47 9 2

5 9 4 06 6 3 2

Count the total number of decimal places in the problem.

1 . 9 8x 3 . 47 9 2

5 9 4 06 6 3 2

Count the total number of decimal places in the problem.

1 . 9 8x 3 . 47 9 2

5 9 4 06 6 3 2

2 decimal places

Count the total number of decimal places in the problem.

1 .9 8x 3 . 47 9 2

5 9 4 06 6 3 2

2 decimal places

+1 decimal place

Count the total number of decimal places in the problem.

1 . 9 8x 3 . 47 9 2

5 9 4 06 6 3 2

2 decimal places

+1 decimal place3 decimal places

Put that many decimal places in the answer.

1 . 9 8x 3 . 47 9 2

5 9 4 06 6 3 2

2 decimal places

+1 decimal place3 decimal places

Put that many decimal places in the answer.

1 . 9 8x 3 . 47 9 2

5 9 4 06 6 3 2

2 decimal places

+1 decimal place3 decimal places

1 decimal place

Put that many decimal places in the answer.

1 . 9 8x 3 . 47 9 2

5 9 4 06 6 3 2

2 decimal places

+1 decimal place3 decimal places

2 decimal places

Put that many decimal places in the answer.

1 . 9 8x 3 . 47 9 2

5 9 4 06.6 3 2

2 decimal places

+1 decimal place3 decimal places

3 decimal places

Put that many decimal places in the answer.

1 . 9 8x 3 . 47 9 2

5 9 4 06.6 3 2

Remove any extra zeros.Find the number that

has the most digits NOT INCLUDING zeros on the front.

Put that number on top lining up the right side of the problem.

Multiply normally.Count the total decimal

places in the problem.Put that many decimal

places in the answer.