Percentages for kids

What kids learn about percentages, grade by grade

• Grade 4 and 5: the groundwork. Fractions out of 100 and decimals to hundredths (4.NF.C.6).
• Grade 6 (6.RP.A.3c): percent as a rate per 100, finding a percent of a number, and finding the whole when you know a part and the percent.
• Grade 7 (7.RP.A.3): multi-step percent problems with sales tax, tips, discounts, markups, simple interest and percent increase and decrease.

Where to start with percentages

Start with 100 squares, money and the easy percents: 50% is half, 25% is a quarter, 10% is a tenth. Once those feel natural, every other percent can be built from them, and the formal methods make sense.

The big idea behind percentages

Percent means per hundred. A percent compares any amount to 100, so different-sized things can be compared fairly. 18 out of 24 and 30 out of 40 are hard to compare, but 75% and 75% are obviously the same.

The three kinds of percent question

Almost every percent problem is one of these three. Spotting which one it is solves half the problem.

Question	You know	Method	Example
Find the part	Percent and whole	percent × whole	25% of 80 = 0.25 × 80 = 20
Find the percent	Part and whole	part ÷ whole × 100	18 of 24 = 18 ÷ 24 = 75%
Find the whole	Part and percent	part ÷ percent	8 is 5% of 8 ÷ 0.05 = 160

Percent tricks for mental math

• 10%: move the decimal point one place left. 10% of 340 = 34.
• 5%: half of 10%. 5% of 340 = 17.
• 20%, 30%…: multiples of 10%. 30% of 340 = 3 × 34 = 102.
• 15% tip: 10% plus half of it. On a $40 bill: $4 + $2 = $6.
• Flip it: 8% of 25 is the same as 25% of 8, which is 2.

Where kids get stuck with percentages

Using the wrong number as the whole

In “18 out of 24”, the whole is 24. In percent change, the whole is always the original amount, not the new one. Ask: “percent of what?”

7% written as 0.7

Percent to decimal always moves two places: 0.07. See converting percents and decimals.

Adding percents that don’t add

A 20% rise then a 20% fall doesn’t get back to the start: 100 → 120 → 96. Each percent is of a different whole.

Mixing up “percent of” and “percent off”

20% of $50 is $10. 20% off $50 leaves $40. Underline the small word before working anything out.

Percentages worksheets

Printable PDFs with answer keys, covering all three kinds of question and grade 7 word problems. Make a fresh percent test or a percent change test.

• Percents and decimalsGrade 6 · converting
• Percent of a numberGrade 6 · find the part
• Finding the percentGrade 6 · what percent?
• Finding the wholeGrade 6 · of what number?
• Percent changeGrade 7 · increase and decrease
• Tax, tip and interestGrade 7 · word problems

How to teach percentages at home

Shop the sales

Next time you see “30% off”, ask your child to work out the new price before you reach the till. Clothes and electronics give good round numbers.

Let them work out the tip

At a restaurant, the 10% and half-of-it trick gives a 15% tip in seconds. It is real, useful and quick.

Watch the battery

Phones and tablets show battery as a percent. “It’s at 60% and drops 5% an hour. How long until it’s at 20%?”

Score sports and tests

Free throws made, goals saved or test marks: turn each into a percent and compare. Was 9 out of 12 better than 14 out of 20? (75% vs 70%.)