Welcome Activity

Estimate:1) 25 ÷ 4.7

2) 40.79 ÷ 7

3) 984.76 ÷ 38.1

5

6

25

10/1/2015 1-2 C Divide Decimals

• To divide a decimal by a whole number, simply divide as usual.

• PLACE THE DECIMAL POINT in the quotient (the answer) DIRECTLY ABOVE its place in the dividend (the number being divided).

Example 1Find 45.9 3

Estimate 45 ÷ 3 = 15

1

– 31 5

5

– 150 9

– 90

.3

45.9 ÷ 3 = 15.3; Compared to the estimate, the quotient is reasonable.

Example 2Find 8.69 22

Place the decimal point.0.

– 6 62 0 9

3

– 1 9811 0 Annex a zero and continue dividing.

– 1100

950

Estimate

8.69 ÷ 22 = 0.395; Compared to the estimate, the quotient is reasonable.

Example 3Owen is purchasing lumber to build a porch. The table shows the cost of the boards. If Owenbuys a 12-foot board, how much does it cost per foot?

Example 3To find the cost per foot, divide $6.48 by 12.

Place the decimal point.0.

– 6 04 8

5

– 480

4

The cost of the board is $0.54 per foot.

Example 4Violeta and her sister are sharing the cost of a digital camera. The camera costs $88.50. If Violeta saved $50 to buy the camera, how much does her sister have left after paying her share of the camera?

Estimate $90 ÷ 2 = 45; $50 – $45 = 5 Step 1 Determine how much Elena will pay for the

camera.

Example 4

Place the decimal point..

– 80 8

4

– 80 5

– 4

4 2

10– 10

0

5

Example 4

$50.00– $44.25

$5.75

$50.00 – $44.25 = $5.75

Violeta has $5.75 left.

Your Turn1) Five dozen eggs cost $10.50. Find the cost of

one dozen. How much change will you receive if you pay for one dozen eggs with a five dollar bill?

2) Meg is purchasing lumber to build a porch. The table shows the cost of the boards. If Meg buys a 10-foot board, how much does it cost per foot?

3) 1.25 ÷ 5

$3.90

$0.58

0.25

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• Decimal Division W.S. I