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Converting tenths to hundredths

Express a fraction with denominator 10 as an equivalent fraction with denominator 100 and use this to add fractions with denominators 10 and 100 (e.g. 3/10 + 4/100 = 34/100)

ages 9 to 108 practice questionsvideo included

What a learner can do afterwards

Rewrite 7/10 as 70/100
Calculate 3/10 + 4/100 = 34/100
Explain why 5/10 = 50/100 using a hundredths grid

The lesson

You already know that a tenth is 1 out of 10 equal parts, like 3/10. A hundredth is 1 out of 100 equal parts. Cut each tenth into 10 smaller pieces and you get 100 pieces in all. So every tenth is worth ten hundredths: multiply the top number and the bottom number by 10.

Tap to shade 3 of the 10 parts.

This bar has 10 strips, and 3 are shaded: 3/10. Cut each strip into 10 tiny pieces and you get 30 shaded pieces out of 100, so 3/10 = 30/100.

Tap to fill the grid, one at a time: 10 rows of 10.

A hundredths grid has 10 rows and 10 columns, 100 small squares in all. Shading 3 whole columns covers 30 of those squares, the same amount as 3/10.

Try it together

Zara has 3/10 of a pizza, and her friend gives her 4/100 more. First she changes 3/10 into hundredths: 3/10 = 30/100. Then she adds: 30/100 + 4/100 = 34/100. Zara now has 34/100 of the pizza.

Good to know

Before adding tenths and hundredths, make sure both fractions have the same bottom number. Change the tenths into hundredths first, then just add the top numbers.

Every tenth equals ten hundredths, so turn tenths into hundredths first, then add the top numbers together.

Watch it

Where it sits

Learn first

Tenths (age 8+)Equivalent fractions (age 9+)

This opens up

Decimals for Tenths & Hundredths

Where this leads

Jobs that lean on this skill. Follow one to see everything it is built on.

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Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.