수와 연산 전체 문제

By looking at the number of zeros in the multiple of ten, we see the number of places we need to move the decimal to the right.

ⓐ

	5.63(10)
There is 1 zero in 10, so move the decimal point 1 place to the right.

ⓑ

	5.63(100)
There are 2 zeros in 100, so move the decimal point 2 places to the right.

ⓒ

	5.63(1,000)
There are 3 zeros in 1,000, so move the decimal point 3 places to the right.
A zero must be added at the end.

ⓐ 25.8 ⓑ 258 ⓒ 2,580

ⓐ 142 ⓑ 1,420 ⓒ 14,200

Remember, you can “move” the decimals in the divisor and dividend because of the Equivalent Fractions Property.

	$-25.65\div (-0.06)$
The signs are the same.	The quotient is positive.
Make the divisor a whole number by “moving” the decimal point all the way to the right.
“Move” the decimal point in the dividend the same number of places.
Divide. Place the decimal point in the quotient above the decimal point in the dividend.
Write the quotient with the appropriate sign.	$-25.65\div (-0.06)=427.5$

587.3

34.25

$0.19

$0.42

	$0.374$
Determine the place value of the final digit.
Write the fraction for 0.374: - The numerator is 374. - The denominator is 1,000.	$\frac{374}{1000}$
Simplify the fraction.	$\frac{2\cdot 187}{2\cdot 500}$
Divide out the common factors.	$\frac{187}{500}$ so, $0.374=\frac{187}{500}$

Did you notice that the number of zeros in the denominator of $\frac{374}{1,000}$ is the same as the number of decimal places in 0.374?

$\frac{117}{500}$

$\frac{3}{125}$

Since a fraction bar means division, we begin by writing $\frac{5}{8}$ as $85.$ Now divide.

$-0.875$

$-0.375$

$2.\overset{-}{45}$

$2.3\overset{-}{18}$

First we must change one number so both numbers are in the same form. We can change the fraction to a decimal, or change the decimal to a fraction. Usually it is easier to change the fraction to a decimal.

		$\frac{7}{8}+6.4$
Change $\frac{7}{8}$ to a decimal.
Add.		$0.875+6.4$
		$7.275$
		So, $\frac{7}{8}+6.4=7.275$

5.275