CONFIDENTIAL 1

Dividing Decimals By Whole Numbers

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LET’S CHECK !!!

• 0.7 x 0.4 =0.28• 21 ÷ 3 = 7• 81÷ 9 =9• 63 ÷ 7 =9• 729 ÷ 81 =9

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Divide a decimal by a 1-digit number

• Divide a decimal by a whole number is similar to dividing whole numbers

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Dividing decimals by a 1-digit number

• Example-1• Find 6.8 ÷ 2 =

Estimate 6 ÷ 2 = 3

2 6.8

-6.0

0 8

8

0

3.4 Place the decimal point directly above the decimal point in the dividend.

Divide as with whole numbers

6.8 ÷ 2 = 3.4. Compared to the estimate, the quotient is reasonable.

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Example -2

3 45.9 - 3 15 - 15 0 9 -9 0

Divide 45.9 ÷ 3 Estimate 48 ÷ 3 = 16.

Place the decimal point

Divide as with whole numbers

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

15.

3

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Example-3

4 3.4900 - 32 29 -28 10 -8 20 -20 0

Find 3.49 ÷ 4

Place the decimal point

Annex a zero and continue dividing.

3.49 ÷ 4 = 0.8725. Compared to the estimate, the quotient is reasonable.

Estimate is 4 ÷4 =1

0.8725

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Let’s try by yourself

Find 7.5 ÷ 3 2.5

3 7.5

-6

15

-15

0

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Multiplying Decimals By a 2-Digit Number

Find 7.49 ÷ 14

14 7.490

-70

0 49

- 42

070

- 70

0

0.535 Place the decimal point

Annex a zero and continue dividing

Estimate is 10 ÷10=1

7.49 ÷14 = 0.535.

Compared to the estimate, the quotient is reasonable.

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Example -2

Find 8.69 ÷ 22.

22 8.690

-66

209

-198

0110

-110

0

0.395

Place the decimal point

Annex a zero and continue dividing.

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Now your turn

Find 114.8 ÷ 14 = 8.2

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Practice Problems

1) 3.5 ÷ 7=0.5 2) 9.6 ÷2 = 4.8

3) 51.79÷3=17.2633

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More Problems

1) 11.4 ÷ 19=0.6

2) 10.22 ÷ 14=0.73

3) 212.8 ÷ 14=15.2

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Have a Break!!!

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Let’s have some fun

http://www.thekidzpage.com/onlinejigsawpuzzles/jigsaw-puzzles/12-piece-jigsaw/010406flamingo.html

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More Practice Problems

1) 39.39 ÷ 3=13.13

2) 8.53 ÷ 6=1.421666

3) 36.8 ÷ 2= 18.4

4) 118.5 ÷ 5= 23.7

5) 55.2 ÷ 46= 1.2

6) 336.75 ÷ 31=10.862

7) 751.2 ÷ 25=30.048

8) 69.904 ÷ 34=2.056

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Word Problems

Q: Britannia and 5 of her friends bought a six-pack of fruit juice after their lacrosse game. If the six-pack costs $3.29, how much does each person owe, if the cost is divided equally ?

A:$3.29÷6 = 0.5483333…………

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Review

♣ Dividing a decimal by a whole number is similar to dividing whole numbers.

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