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Math Help: How to Work Out a Fraction of a Number

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Mark, a math enthusiast, loves writing tutorials for stumped students and those who need to brush up on their math skills.

Learn how to find any fraction of any number using the simple process outlined here.

Learn how to find any fraction of any number using the simple process outlined here.

Whether you're a student doing homework, a chef working on a recipe, a wedding planner trying to lay out a budget, or just an average person strolling through life, chances are you'll eventually need to figure out a fraction of a number. In this article, we'll define a few simple terms, learn how to find any fraction of any number, and explore some example problems for practice. Ready? Let's do it!

Important Terms

  • Fraction: A fraction is a portion of a whole. Think of it in terms of pizza—if there are 10 slices total in a pizza pie, and you've had three pieces, that means you've eaten 3/10 (three tenths) of the pie. The fraction 3/10 represents the portion of the whole pizza you've eaten.
  • Numerator: In a fraction, the numerator is the number on top of (or before) the line. In the example above, 3 is the numerator of the fraction 3/10.
  • Denominator: In a fraction, the denominator is the number below (or after) the line. In the example above, 10 is the denominator of the fraction 3/10.

How to Find a Fraction of a Number

To work out a fraction of a number, all you need to do is divide that number by the denominator of the fraction, then multiply your result by the numerator of the fraction.

For instance, if we wanted to find out what 3/8 of 24 is, we would divide 24 by 8 (the denominator of the fraction).

24 ÷ 8 = 3

We would now multiply this result by 1 (the numerator of the fraction).

3 x 3 = 9

So, 3/8 of 24 is 9.

Video Demonstration

Example Problems

Remember—to work out a fraction of a number, all you need to do is divide that number by the denominator of the fraction and then multiply the result by the numerator of the fraction. Let's do some example problems for practice.

Example 1: Work out 3/8 of 48

First, divide 48 by the denominator:

48 ÷ 8 = 6 (this is 1/8 of 48)

Now, multiply this result by the numerator:

6 × 3 = 18 (this is 3/8 of 48)

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So, 3/8 of 48 is 18.

Example 2: Work out 2/9 of 36

First, divide 36 by the denominator:

36 ÷ 9 = 4 (this is 1/9 of 36)

Now, multiply this result by the numerator:

4 × 2 = 8 (this is 2/9 of 36)

So, 2/9 of 36 is 8.

Example 3: Work out 4/5 of 60

First, divide 60 by the denominator:

60 ÷ 5 = 12 (this is 1/5 of 60)

Now, multiply this result by the numerator:

12 × 4 = 48 (this is 4/5 of 60)

So, 4/5 of 60 is 48.

Example 4: Work out 5/11 of 77

First, divide 77 by the denominator:

77 ÷ 11 = 7 (this is 1/11 of 77)

Now, multiply this result by the numerator:

7 × 5 = 35 (this gives 5/11 of 77)

So, 5/11 of 77 is 35.

Example 5: Word Problem

A fuel tank holds 14 gallons of fuel when full. If the tank has 3/7 of fuel left in the tank, work out how many gallons of fuel are left.

Here, you need to calculate 3/7 of 14 gallons

First, divide 14 by the denominator:

14 ÷ 7 = 2 (this is 1/7 of 14)

Now, multiply this result by the numerator:

2 × 3 = 6 (this is 3/7 of 14)

So, there are 6 gallons of fuel left in the tank.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: 12 is 3/4 of what number?

Answer: You need to divide by the top and multiply by the bottom.

12 divided by 3 is 4, and 4 times 4 is 16.

Question: What is 1/7 of 3.50?

Answer: Just divide 3.50 by 7 as 1/7 means divide by 7. This will give an anwer of 0.5.

Question: What is 1/8 of an hour?

Answer: 60 divided by 8 is 7.5, so 7.5 minutes.

Question: What is 1/4 of 24?

Answer: A quarter can be found by halving the number twice.

Half of 24 is 12, and half of 12 is 6.

Question: What is 5/7 of 84?

Answer: 84 divided by 7 gives 12, and 12 mulplited by 5 gives 60.

Question: Can you work out 5/6 of 84?

Answer: Fisrt work out 84 divided by 6 to give 14. Now multiply 14 by 5 to give 70.

Question: How do you calculate 1/7 x 4?

Answer: 4 can be written as a fraction as 4/1.

Now, multiply the two fractions together 1/7 times 4/1 = 4/7.

Question: What is 12/15 of 7?

Answer: First cancel 12/15 to 4/5.

Now work out 7 divided by 5 to give 1.4, and then 1.4 times 4 to give 5.6.

Question: What is 3/8 of 42?

Answer: 42 divided by 8 is 5.25, and 5.25 times 3 is 15.75.

Follow the rule divide by the bottom and times by the top.

Question: What is 5/6 of 48?

Answer: First work out 48 divided by 6 which is 8.

Now multiply 8 by 5 to give a final answer of 40.

Question: What is 1 5/8 of 56?

Answer: Convert the mixed number to an improper fraction which is 13/8.

Now work out 13/8 of 56 by using the rule divide by the bottom and times by the top.

56 divided by 8 is 7, and 13 times 7 is 91.

Question: What is the quotient of 7÷2/3?

Answer: Write 7 as a fraction as 7/1.

So work out 7/1 divided by 2/3.

Use the rule keep, flip and change to give 21/2.

Question: Can you tell me how do we get the answer to one ninth of a number is 6. What is the number?

Answer: Just multiply the 6 by 9 to give 54. So the number you are looking for is 54.

Question: What is 1/4 of 320?

Answer: To find 1/4 of any number divide the number by 4 to give 80.

Question: What is 4/5 of 60?

Answer: 60 divided by 5 is 12, and 12 times 4 is 48.

Question: What is 1/5 of 65?

Answer: Just divide the number by 5 when working out one fifth of a number.

The answer will be 13.

Question: 4/7 of 48 is about?

Answer: First round 48 to the nearest multiple of 7 which is 49.

Now work out 4/7 of 49.

49 divided by 7 is 7, and 7 times 4 is 28.

So the answer will be about 28.

Question: What is 1/1 of 1?

Answer: The answer will be 1 too (1 divided by 1 is 1, and 1 times 1 is 1).

Question: What part of 5 3/5 is 7/10?

Answer: You will need to divide 7/10 by 5 3/5.

Convert 5 3/5 into an improper fraction which is 28/5

Now work out 7/10 divide by 28/5 which is the same as 7/10 times.

The answer is 1/8.

Question: 4% of a number is what fraction of that number?

Answer: To answer this question convert 4% into a fraction and simplify.

4% means 4 out of 100 so the fraction is 4/100.

Now simplify 4/100 by dividing the numerator and denominator by 4.

This gives a final answer of 1/25.

Question: What fraction of 48 is 12?

Answer: Write 12 on the numerator of the fraction, and 48 on the denominator of the fraction.

Next cancel the fraction down by dividing the numerator and denominator by 12 to give 1/4.

Question: What is 1 1/2 x 60?

Answer: It's probably best to convert 1 1/2 to 1.5, and then work out 1.5 multiplied by 60 to give 90.

Question: What is 3\5 of 56?

Answer: Follow the method divide by the denominator and times by the numerator.

56 divided by 5 is 11.2, and 11.2 times 3 is 33.6

Question: For what number is 27 3/4ths?

Answer: First, divide 27 by 3 to give 9, and then multiply 9 by 4 to give 36.

Question: What is 1/9 of 96?

Answer: To work out one ninth of a number divide the number by 9.

So 96 divided by 9 gives 10.7 (rounded to 1 decimal place).

Question: What is 4/7 more than 63?

Answer: You need to use the rule "divide by the bottom and times by the top". 63 divided by 7 = 9, and 9 multiplied by 4 is 36. Finally add the 36 on to the 63 to give 99.

Question: What is 4/7 of 14?

Answer: Follow the rule, "divide by the bottom and times by the top".

So 14 divided by 7 = 2, and 2 multiplied by 4 = 8.

Question: What is 1/8 of 6?

Answer: To find 1/8 divide the number by 8.

6 divided by 8 gives 0.75.

Question: What is 1/8 of 14?

Answer: 1/8 of a number can be found by dividing the number by 8.

So 14 divided by 8 gives 1.75.

Question: What is 1/5 of 7?

Answer: 1/5 of a number can be found by dividing the number of 5.

Therefore, 7 divided by 5 gives 1.4

Question: How do you figure out what is 5/8 of 4/5?

Answer: You can still use the rule divide by the bottom and times by the top even if your amount is a fraction.

Divide 4/5 by 8 to give 1/10, now multiply 1/10 by 5 to give 1/2.

Question: What is 5/7 of 100?

Answer: Divide 100 by 7 to get 14.28. 14.28 multiplied by 5 is 71.4, rounded to 1 decimal place.

Question: 8% of 60 is 1/5 of what number?

Answer: First work out 8% of 60 which is 4.8.

So one fifth of something is 4.8.

Since 1/5 means divide by 5, multiply 4.8 by 5 to find the missing number.

The asnwer will be 24.

Question: What is 3/6 of 248?

Answer: Its probably easier to cancel 3/6 down to 1/2, so you need to work out one half of 248.

So 248 divided by 2 gives 124.

Question: What is 5/8 of 40 ?

Answer: 40 divided by 8 is 5, and 5 multiplied by 5 is 25.

Question: What is 1/9 of 12?

Answer: To find 1/9 of a number divide the number by 9.

12 divided by 9 is 4/3 or 1.3 recurring.

Question: What is 1/5 of 8?

Answer: To work out 1/5 divide the number by 5.

8 divided by 5 is 1.6.

Question: If 1/9 is 49 what is the number?

Answer: Just multiply 49 by 9 to give 441.

Question: Can you work out 3/12 of 48?

Answer: Follow the rule divide by the denominator and multiply by the numerator.

48 divided by 12 gives 4, and 4 multiplied 3 gives 12.

Question: Orla spent one-quarter of her money on a t-shirt, and 3 eighths on a jumper. What fraction of her money had she left?

Answer: She spent 5/8 on clothes if you add the two fractions together, so 3/8 are left over.

Question: What is 9/13 of 182?

Answer: Divide 182 by 13 to give 14, then multiply 14 by 9 to give 126.

Question: What is 6/8 of 40?

Answer: 40 divided by 8 is 5, and 5 multiplied by 6 is 30.

Question: What is 1/7 0f 15000?

Answer: To work out 1/7 of a number divide the number by 7.

So 15000 divided by 7 gives 2142.86 rounded to decimal places.

Question: 2/3 of a number is 24. What is 5/9 of the number?

Answer: First divide 24 by to to give 12, and multiply 12 by 3 to give 36.

Now find 5/9 of 36, by dividing 36 by 9 to give 4, and multiplying 4 by 5 to give 20.

Question: What is 4/5 of 30?

Answer: First work out 1/5 of the number by dividing by 5, so 30 divided by 5 is 6.

Now work out 4/5 by mutiplying the answer by 4, so 6 multiplied by 4 gives 24.

Question: What is 4/11 of 66?

Answer: Use the method divide by the bottom and times by the top.

66 divided by 11 is 6, and 6 times 4 is 24.

Question: What is 4/5 of 12?

Answer: Follow the rule divide by the bottom and multiply by the top.

12 divided by 5 is 2.4, and 2.4 times 4 is 9.6.

Question: What is 1/3 of 5.28 million?

Answer: To work out 1/3 you just need to divide your number by 3. So 5,280,000 divided by 3 is 1,760,000.

Question: What is 6/11 divided by 3?

Answer: First work out 3 divide by 11 to give 0.27..., and 0.27... multiplied by 6 gives 1.64 to 2 decimal places.

Question: What is 1\5 x 4\5?

Answer: Just multiply the numerators and denominators together of both fractions to give 4/25.

© 2011 Mark

Comments

Offenderman on April 22, 2018:

Rose? Anyone?

bum face on February 21, 2013:

Thanks this helped!!! Xxxxxx

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