Percents (Grade 6)

The rule for changing a percent to a decimal or a fraction, worked examples for finding a percent of a number, a free online practice with instant checking, and printable worksheets with an answer key.

A percent is a number of hundredths: n% means n/100. To change a percent to a decimal, move the decimal point two places to the left, and to find a percent of a number, multiply the number by that decimal.

Percent means per hundred. When you see 30%, it means 30 out of every 100, or the fraction 30/100. Percent problems are fraction and decimal problems written in a different way.

To change a percent to a decimal, drop the % sign and move the decimal point two places to the left: 30% = 0.30, 5% = 0.05, 75% = 0.75. To change a percent to a fraction, write it over 100 and simplify: 75% = 75/100 = 3/4.

To find a percent of a number, change the percent to a decimal and multiply. For 5% of 480, change 5% to 0.05 and multiply: 0.05 × 480 = 24. For 75% of 400, multiply 0.75 × 400 = 300.

Some problems give the percent and the result, and ask for the starting number. If 30% of a number is 144, divide 144 by 0.30: 144 ÷ 0.30 = 480. Divide when you are looking for the whole number, multiply when you are looking for a part of it.

To check your work, turn the problem around. If 30% of 380 is 114, then multiplying should give it back: 380 × 0.30 = 114. If the numbers match, your answer is right.

Worked examples

20% of 340 = 68

25% of 80 = 20

75% of 440 = 330

Practice: solve 10 problems

Examples with answers

Problem	Answer
20% of a number is 80. Find the number.	400
75% of 320	240
5% of 300	15
30% of a number is 90. Find the number.	300
20% of a number is 28. Find the number.	140
60% of 340	204
60% of 420	252
60% of 180	108
15% of 460	69
75% of a number is 30. Find the number.	40
50% of a number is 50. Find the number.	100
15% of a number is 66. Find the number.	440

Common mistakes

Multiplying by the percent instead of the decimal

30% of 380 is not 30 × 380. Change the percent to a decimal first: 0.30 × 380 = 114.

Moving the decimal point the wrong way

5% is 0.05, not 0.5. Move the decimal point two places left: 5% of 480 is 0.05 × 480 = 24, not 240.

Multiplying instead of dividing for the whole number

If 30% of a number is 144, you need the whole number, so divide: 144 ÷ 0.30 = 480, not 144 × 0.30.

Practice in the game

Each right answer builds a tower that defends the fortress. Free, no sign-up, phone or computer.

For parents: practising at home

Practice a few percent problems every day instead of a long worksheet once a week. Ask your child to say the steps out loud: change the percent to a decimal, then multiply or divide. If they mix up when to multiply and when to divide, go back to easy examples like 10% of 100, where the answer is simple to picture.

For tutors

Assign percents to a student in ZnayQuest: they practice at home in the game, and you see every mistake, what they answered and the correct answer, so you know which step they get wrong.

Assign this topic to a student — 3 lessons free

FAQ

How do you change a percent to a decimal?

Drop the % sign and move the decimal point two places to the left. For example, 30% = 0.30 and 5% = 0.05.

How do you change a percent to a fraction?

Write the percent over 100 and simplify. For example, 75% = 75/100 = 3/4.

Is it free?

Yes. The lesson, the practice and the worksheets are free, with no sign-up.