Lesson: Multiplying and Dividing Fractions

Multiple Choice

Is 12 the LCM of 3 and 4?

• YES

• NO

Multiplying and Dividing Fractions

Objective: Multiply and Divide Fractions

​Understanding Multiplying Fractions

​When you multiply by a number greater than one it makes the original bigger.

​Understanding Multiplying Fractions

​When you multiply by a number less than one it makes the original smaller.

Multiple Select

Which products are less than 10?

• $$10\times\frac{3}{4}$$  

• $$10\times\frac{9}{8}$$  

• $$10\times4\frac{2}{3}$$  

• $$10\times\frac{1}{2}$$  

• $$10\times\frac{4}{7}$$  

​How to Multiply Fractions

​Simple: Multiply the numerators and multiply the denominators.

​Then simplify if needed.

Math Response

$$\frac{3}{7}\times\frac{2}{5}=$$  

Type answer here

Correct Answer: \frac{6}{35}

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Math Response

$$\frac{3}{4}\times12=$$  

Type answer here

Correct Answer: 9

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​How to Multiply Mixed Numbers

Rewrite the mixed number as an improper fraction.

Multiply the numerators and multiply the denominators.

​Then simplify if needed.

Math Response

$$5\frac{1}{4}\times\frac{3}{7}=$$  

(answer is a mixed number)

Type answer here

Correct Answer: 2\frac{1}{4}

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Moving into Dividing Fractions​

​How to Divide Fractions

FLIP the second fraction (reciprocal)​

Multiply the across.

​Then simplify if needed.

Math Response

$$\frac{3}{4}\div\frac{1}{2}=$$  

(answer is a mixed number)

Type answer here

Correct Answer: 1\frac{1}{2}

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Math Response

$$3\div\frac{7}{8}=$$  

(answer is a mixed number)

Type answer here

Correct Answer: 3\frac{3}{7}

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​How to Divide Mixed Numbers

​Rewrite the whole number as a fraction (put it over 1)

FLIP the second fraction (reciprocal)​

Multiply the numerators and multiply the denominators.

​Then simplify if needed.

Math Response

$$2\frac{1}{3}\div4\frac{3}{8}=$$  

Type answer here

Correct Answer: \frac{8}{15}

Deg^°

Rad

Open Ended

On a scale 1 to 10, how confindent are you on multiplying and dividing with fractions?