Chapter 2 Review

Chapter 2-Fractions and Decimals

Review

Section 2.1

Multiplying Fractions

Key Idea

• Multiply the numerators and multiply the denominators.

•  $\frac{3}{7}\times\frac{1}{2}=\frac{3\times1}{7\times2}=\frac{3}{14}$  

•  $\frac{a}{b}\cdot\frac{c}{d}=\frac{a\cdot c}{b\cdot d},\ where\ b,\ d\ \ne0$  

Multiplying Mixed Numbers

Write each mixed number as an improper fraction. Then multiply as you would with fractions.

Section 2.2

Dividing Fractions

Vocabulary

• Reciprocals - Two numbers whose product is 1

• Multiplicative Inverses - Two numbers whose product is 1

Key Idea

• To divide a number by a fraction, multiply the number by the reciprocal of the fraction.

•  $\frac{1}{5}÷\frac{3}{4}=\frac{1}{5}\times\frac{4}{3}=\frac{1\times4}{5\times3}$  

•  $\frac{a}{b}÷\frac{c}{d}=\frac{a}{b}\cdot\frac{c}{d}=\frac{a\cdot c}{b\cdot d},\ wehre\ b,\ c,\ and\ d\ \ne0$  

Section 2.3

Dividing Mixed Numbers

Key Idea

Write each mixed number as an improper fraction. Then divide as you would with proper fractions.

Section 2.4

Adding and Subtracting Decimals

Key Idea

To add or subtract decimals, write the numbers vertically and line up the decimal points. Then bring down the decimal point and add or subtract as you would with whole numbers.

Section 2.5

Multiplying Decimals

Key Idea

• Multiply as you would with whole numbers. Then count the number of decimal places in the decimal factor. The product has the same number of decimal places.

•  $13.91\times7=97.37\$  Notice that there are 2 decimal places in both the problem and the solution.

Section 2.6

Dividing Whole Numbers

Section 2.7

Dividing Decimals

Key Idea

• Place the decimal point in the quotient above the decimal point in the dividend. Then divide as you would with whole numbers. Continue until there is no remainder.

Key Idea

Multiply the divisor and the dividend by a power of 10 to make the divisor a whole number. Then place the decimal point in the quotient above the decimal point in the dividend and divide as you would with whole numbers. Continue unitl there is no remainder