6th Grade Math Textbook, Fundamentals

Three ways to check:

• Multiply the quotient by the original
  divisor, 1.6.
  6.25 quotient

1. 6 divisor
   3750
    625
   10.000 original dividend

• You can also compare the actual answer to the estimate. The actual
  answer, 6.25, is close to the estimate of 5, so the answer is reasonable.

So 10 1.6 6.25. The race is about 6.25 miles long.

You can find the quotient of two rational numbers that have unlike signs.

Divide: 3 (0.075)

0.075(1000)  (^75) 0 075 3(1000)  3000
40

.. 3 000.

.

.





 &KDSWHU

4-8

Update your skills. See page 413 XIV.

Divide Decimals

Objective To divide positive and negative decimals • To evaluate division expressions

containing decimals

The town of Holly Hills holds an annual 10-km race to
raise money for charity. If a mile is about 1.6 kilometers,
about how many miles is the Holly Hills 10-km race?

To find about how many miles are in a 10-km race,

divide: 10 km 1.6 km

First estimate by using compatible numbers: 10  2  5

Then divide the actual numbers. Write placeholder zeros

in the dividend to complete the division.

1.6(10)  16 16 10(10)  100

625

.^10000

.

...

• Use a calculator to check.
  Press 1.6 6.25
  10. original dividend

Check:Multiply (40)(0.075)

0.075

 40

3.000 original dividend

The quotient of two rational numbers

with unlikesigns is negative.

3 0 0

00

So 3 (0.075) 40.

Key Concept

Dividing with Decimals

• Multiply both the dividend and the
  divisor by the least power of 10 to
  form an integer divisor.


• Align the decimal point in the
  quotient with the decimal point in
  the dividend.


• Divide as with integers.


• Check by multiplying.

 96

40

 32

80

 80

0