Multiply/Divide Rational Numbers

Multiply/Divide Rational Numbers

Multiplying Decimals

• Ignore decimal points & set up like a regular multiplication problem

• Multiply

• Count number of digits behind decimal point in problem & place with the same number of digits behind in the solution

Multiple Choice

Find the product of (-2.72) • 3.5

• 9.52

• -9.52

• 6.36

• -6.36

Poll

How confident are you with multiplying decimals?

• Very Confident

• Somewhat Confident

• Confident

• Not so Confident

Dividing Decimals

• Move decimal point to make the divisor (outside number) a whole number

• Move decimal point same number of places in the dividend (inside number)

• Place decimal up into the quotient (answer) and then divide

Multiple Select

Find the quotient of (-14.56) ÷ (-0.4)

• -36.4

• 36.4

• 3.64

• -3.64

Poll

How confident are you with dividing decimals?

• Very Confident

• Somewhat Confident

• Confident

• Not so Confident

Multiplying Fractions

• Multiply numerators; Multiply denominators

• Simplify!

• **Mixed numbers must be an improper fraction**

Multiple Choice

Find the product of: 

$$3\ \frac{\text{1}}{\text{4}}\ •\ \left(-\frac{\text{2}}{\text{3}}\right)$$  

• $$3\frac{\text{2}}{\text{12}}$$  

• $$-3\frac{\text{1}}{\text{6}}$$  

• $$-2\frac{\text{1}}{\text{6}}$$  

• $$2\frac{\text{4}}{\text{12}}$$  

Poll

How confident are you with multiplying fractions?

• Very Confident

• Somewhat Confident

• Confident

• Not so Confident

Dividing Fractions

• Keep the first fraction the same

• Multiply by the reciprocal (change numerator & denominator of second fraction)

• Simplify, if needed!

• **Mixed numbers must be improper fractions**

Multiple Choice

Find the quotient:

$$\left(-2\frac{\text{1}}{\text{5}}\right)\ ÷\ \left(\frac{\text{-1}}{\text{3}}\right)$$  

• $$-2\frac{\text{3}}{\text{5}}$$  

• $$6\frac{\text{3}}{\text{5}}$$  

• $$-6\frac{\text{3}}{\text{5}}$$  

• $$2\frac{\text{3}}{\text{5}}$$  

Poll

How confident are you with dividing fractions?

• Very Confident

• Somewhat Confident

• Confident

• Not so Confident