 # Decimals

Dividing Decimals
How to divide a decimal by a whole number and how to divide a decimal by a decimal?
Dividing a decimal by a whole number
1. Place a decimal point in the answer directly above the decimal point in the dividend.
2. Divide as if there were no decimal point involved.
Examples:
15.2 ÷ 4
42.2 ÷ 3
Dividing by a decimal
1. If the divisor is a decimal, change it to a whole number by moving the decimal point to the right as many places as necessary.
2. Then move the decimal point in the dividend to the right the same number of places. 3. Place the decimal point in the answer directly above the decimal point in the dividend.
4. Divide until the remainder becomes zero, or the remainder repeats itself, or the desired number of decimal places is achieved.
Examples:
67.08 ÷ 2.6
12 ÷ 0.36
Multiplying Decimals
1. Multiply the numbers just as you would multiply whole numbers.
2. Find the sum of the decimal places in the factors.
3. Place the decimal point in the product so that the product has the same number of decimal places as the sum of decimal places. You may need to add zeros to the left of the number.
Examples:
5.2 x 0.2
12.3 x 0.15
0.002 x 15.78

Percent
Conversion between Fractions, Percents, and Decimals
Percentage is a way of expressing a number as a fraction of 100. It is denoted using the percent sign, %.
Three kinds of notation for percentages: Percent, Fraction, Decimal
Percent to Fraction
1. Write p over 100. 2. Simplify.
Percent to Decimal
1. Drop %
2. Divide by 100 (or move decimal 2 places to the left)
Decimal to Percent
1. Multiply by 100.
Decimal to Fraction
1. Write as a fraction with a denominator of 1.
2. Multiple the numerator and denominator by powers of 10 to eliminate any decimals.
3. Simplify.
Fraction to decimal
1. Divide the numerator by the denominator
2. Multiply by 100

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