6th Grade Math Textbook, Progress

Decimal Divisors

3-8

Mrs. Martinez is shingling the roof of

her house. Each shingle is 0.2 m wide.

If the roof is 8.46 m wide, how many

shingles can she put in each row?

To find the number of shingles, n,

divide: 8.46
0.2n.

First estimate by using front-end estimation:

8 
0.240.

Then divide.

To divide by a decimal:


Move the decimal point in the divisor

to form a whole-number divisor. Then

move the decimal point in the dividend

to the right the same numberof places.

Place the decimal point in the quotient

and then divide.

Check by multiplying.

Each row will have 42.3 shingles.

Study these examples.

0.2
 8 .4 6

4 2. 3

2 
 8  4 . 6

4 2. 3

 4 0.2

8.4 6

Think

42.3 is close to the estimate of 40.

2 2 2 0 .5 3 1 6 6

2.4
 1 .2 7  2 2 4
 1  2 . 7  2 0. 0 2 7
 0 .1 6  2 2 7
 1  6  2

1 2 0 1 6 2

2 2 7 2 6 6  0

2 2 7 2

2 2  70

Remember: The divisormust always

be a whole number.

Move the decimal

points one place

to the right.

Move the decimal

points three places

to the right.

2.0

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