ISEE Middle Level Math : How to multiply fractions

Study concepts, example questions & explanations for ISEE Middle Level Math

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Example Questions

Example Question #51 : How To Multiply Fractions

Multiply the following:

\(\displaystyle \frac{5}{7} \cdot \frac{1}{4}\)

Possible Answers:

\(\displaystyle \frac{5}{28}\)

\(\displaystyle \frac{6}{11}\)

\(\displaystyle \frac{6}{28}\)

\(\displaystyle \frac{5}{7}\)

\(\displaystyle \frac{27}{28}\)

Correct answer:

\(\displaystyle \frac{5}{28}\)

Explanation:

To multiply fractions, we will multiply the numerators together, then we will multiply the denominators together.  Note that we do NOT need to find a common denominator. 

\(\displaystyle \frac{5}{7} \cdot \frac{1}{4}\)

\(\displaystyle \frac{5 \cdot 1}{7 \cdot 4}\)

\(\displaystyle \frac{5}{28}\)

Example Question #382 : Numbers And Operations

Multiply the following:

\(\displaystyle \frac{1}{3} \cdot \frac{2}{7}\)

Possible Answers:

\(\displaystyle \frac{1}{7}\)

\(\displaystyle \frac{2}{21}\)

\(\displaystyle \frac{3}{21}\)

\(\displaystyle \frac{3}{10}\)

\(\displaystyle \frac{13}{21}\)

Correct answer:

\(\displaystyle \frac{2}{21}\)

Explanation:

To multiply fractions, we will multiply the numerators together, then we will multiply the denominators together.  Note that we do NOT have to find a common denominator.  

So, we get

\(\displaystyle \frac{1}{3} \cdot \frac{2}{7}\)

\(\displaystyle \frac{1 \cdot 2}{3 \cdot 7}\)

\(\displaystyle \frac{2}{21}\)

Example Question #382 : Numbers And Operations

Multiply the following:

\(\displaystyle \frac{3}{4} \cdot \frac{1}{4}\)

Possible Answers:

\(\displaystyle \frac{3}{4}\)

\(\displaystyle 2\)

\(\displaystyle \frac{4}{8}\)

\(\displaystyle \frac{3}{16}\)

\(\displaystyle 1\)

Correct answer:

\(\displaystyle \frac{3}{16}\)

Explanation:

To multiply fractions, we will multiply the numerators together, then we will multiply the denominators together.  Note that we do NOT need to find a common denominator.

So, we will multiply:

\(\displaystyle \frac{3}{4} \cdot \frac{1}{4}\)

\(\displaystyle \frac{3 \cdot 1}{4 \cdot 4}\)

\(\displaystyle \frac{3}{16}\)

Example Question #231 : Fractions

Multiply the following:

\(\displaystyle \frac{8}{9} \cdot \frac{1}{4}\)

Possible Answers:

\(\displaystyle \frac{8}{13}\)

\(\displaystyle \frac{2}{8}\)

\(\displaystyle \frac{9}{13}\)

\(\displaystyle \frac{8}{45}\)

\(\displaystyle \frac{2}{9}\)

Correct answer:

\(\displaystyle \frac{2}{9}\)

Explanation:

To multiply fractions, we will multiply the numerators together, then we will multiply the denominators together.  Note that we do NOT need to find a common denominator.

So,

\(\displaystyle \frac{8}{9} \cdot \frac{1}{4}\)

Before we multiply, we can simplify to make things easier.  The 8 and the 4 can both be divided by 4.  So,

\(\displaystyle \frac{2}{9} \cdot \frac{1}{1}\)

Now, we can multiply straight across.  We get

\(\displaystyle \frac{2 \cdot 1}{9 \cdot 1}\)

\(\displaystyle \frac{2}{9}\)

Example Question #381 : Numbers And Operations

Multiply the following:

\(\displaystyle \frac{5}{6} \cdot 7\)

Possible Answers:

\(\displaystyle \frac{12}{6}\)

\(\displaystyle 7\)

\(\displaystyle \frac{35}{42}\)

\(\displaystyle \frac{35}{6}\)

\(\displaystyle \frac{5}{42}\)

Correct answer:

\(\displaystyle \frac{35}{6}\)

Explanation:

To multiply fractions, we will multiply the numerators together, then we will multiply the denominators together.  Note that we do NOT need to find a common denominator. 

So,

\(\displaystyle \frac{5}{6} \cdot 7\)

We must write 7 as a fraction.  We know that whole numbers can be written as fractions over 1.  So,

\(\displaystyle \frac{5}{6} \cdot \frac{7}{1}\)

Now, we can multiply straight across.  We get

\(\displaystyle \frac{5 \cdot 7}{6 \cdot 1}\)

\(\displaystyle \frac{35}{6}\)

Example Question #241 : Fractions

Multiply the following:

\(\displaystyle \frac{2}{3} \cdot 18\)

Possible Answers:

\(\displaystyle 8\)

\(\displaystyle 15\)

\(\displaystyle 6\)

\(\displaystyle 12\)

\(\displaystyle 9\)

Correct answer:

\(\displaystyle 12\)

Explanation:

To multiply fractions, we will multiply the numerators together, then we will multiply the denominators together.  Note that we do NOT need to find a common denominator. 

So, in the problem

\(\displaystyle \frac{2}{3} \cdot 18\)

We will first write 18 as a fraction.  We know that whole numbers can be written as a fraction over 1.  So, we get

\(\displaystyle \frac{2}{3} \cdot \frac{18}{1}\)

Now, before we multiply, we can simplify to make things easier.  The 3 and the 18 can both be divided by 3.  We get

\(\displaystyle \frac{2}{1} \cdot \frac{6}{1}\)

Now, we can multiply straight across.  We get

\(\displaystyle \frac{2 \cdot 6}{1 \cdot 1}\)

\(\displaystyle \frac{12}{1}\)

\(\displaystyle 12\)

Example Question #391 : Numbers And Operations

Multiply the following:

\(\displaystyle \frac{7}{8} \cdot \frac{2}{3}\)

Possible Answers:

\(\displaystyle \frac{9}{11}\)

\(\displaystyle \frac{2}{3}\)

\(\displaystyle \frac{9}{24}\)

\(\displaystyle 4\)

\(\displaystyle \frac{7}{12}\)

Correct answer:

\(\displaystyle \frac{7}{12}\)

Explanation:

To multiply fractions, we will multiply the numerators together and the denominators together.  We get

\(\displaystyle \frac{7}{8} \cdot \frac{2}{3}\)

 

\(\displaystyle \frac{7 \cdot 2}{8 \cdot 3}\)

 

\(\displaystyle \frac{14}{24}\)

 

\(\displaystyle \frac{7}{12}\)

Example Question #51 : How To Multiply Fractions

Multiply the following:

\(\displaystyle \frac{7}{8} \cdot \frac{1}{2}\)

Possible Answers:

\(\displaystyle \frac{7}{4}\)

\(\displaystyle \frac{3.5}{4}\)

\(\displaystyle \frac{8}{10}\)

\(\displaystyle \frac{7}{16}\)

\(\displaystyle \frac{15}{16}\)

Correct answer:

\(\displaystyle \frac{7}{16}\)

Explanation:

To multiply, we will multiply the numerators together and the denominators together. We get

\(\displaystyle \frac{7}{8} \cdot \frac{1}{2}\)

 

\(\displaystyle \frac{7 \cdot 1}{8 \cdot 2}\)

 

\(\displaystyle \frac{7}{16}\)

Example Question #392 : Numbers And Operations

Multiply the following:

\(\displaystyle \frac{5}{7} \cdot \frac{1}{2}\)

Possible Answers:

\(\displaystyle \frac{2}{3}\)

\(\displaystyle \frac{6}{9}\)

\(\displaystyle \frac{5}{9}\)

\(\displaystyle \frac{5}{14}\)

\(\displaystyle \frac{6}{14}\)

Correct answer:

\(\displaystyle \frac{5}{14}\)

Explanation:

To multiply, we will multiply the numerators together, then we will multiply the denominators together.  So, we get

\(\displaystyle \frac{5}{7} \cdot \frac{1}{2}\)

 

\(\displaystyle \frac{5 \cdot 1}{7 \cdot 2}\)

 

\(\displaystyle \frac{5}{14}\)

Example Question #393 : Numbers And Operations

Multiply the following:

\(\displaystyle \frac{7}{9} \cdot \frac{2}{3}\)

Possible Answers:

\(\displaystyle \frac{16}{24}\)

\(\displaystyle \frac{2}{3}\)

\(\displaystyle \frac{14}{28}\)

\(\displaystyle \frac{18}{21}\)

\(\displaystyle \frac{14}{27}\)

Correct answer:

\(\displaystyle \frac{14}{27}\)

Explanation:

To multiply fractions, we will multiply straight across.  In other words, we will multiply the numerators together, then we will multiply the denominators together. So, we get

\(\displaystyle \frac{7}{9} \cdot \frac{2}{3}\)

 

\(\displaystyle \frac{7 \cdot 2}{9 \cdot 3}\)

 

\(\displaystyle \frac{14}{27}\)

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