Same Math › Grades 6–7 › Percent bars
What is a percent bar?
A percent bar is a rectangle that stands for the whole, 100%, split into ten equal parts of 10% each. To find 30% of 80, split 80 into ten parts of 8, then take three of them: 24. The same picture handles discounts, tips and percent change.
- The whole bar is 100%: here, 80.
- Each tenth is 10%: 80 ÷ 10 = 8.
- 30% = 3 tenths = 24
Why schools teach it
One picture for every kind of percent problem
Sixth graders find a percent of a quantity (6.RP.A.3c), and seventh graders solve multi-step problems like discounts, tax, tips and percent increase (7.RP.A.3). Kids often know a formula but not which numbers go where.
The bar makes the question visible: is the whole known, or a part? Is the price going up or down? Once the picture is right, the arithmetic is easy.
At the kitchen table
What to say, and what to skip
Say this
What's the whole? That's 100%.
What is 10% of it?
Divide by 10.How many tenths do you need?
Is the new price more or less than the old one?
For discounts and increases.
Skip this
- Starting with is over of equals percent over 100.It works, but kids mix up which number goes where. The bar shows it.
- Moving the decimal point without saying why.Say “10% is one tenth,” then move it.
A 20% discount then a 20% increase gets you back.
It doesn't. The second 20% is of a smaller amount.
See it in action
A $40 shirt is 25% off
Draw the bar: whole = $40, quarters of $10
25% = $10Cross off the discount
$40 − $10What's left is the sale price
$30
For 25%, 50% and 75%, a bar split into quarters is quicker than tenths.
Free practice sheet
Make a percent bar sheet
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Parents also ask
Why tenths?
10% is easy: divide by 10. Every other percent builds from it.
What about percents like 15%?
10% plus half of 10%.
How does percent change work?
Find the change, then ask what percent the change is of the original amount.
Is this the same as a tape diagram?
Yes, it's a tape diagram used for percents.