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Common Core Math4th GradeFractions

4.NF.5: Add Tenths and Hundredths

Also written as 4.NF.C.5 and CCSS.MATH.CONTENT.4.NF.C.5 · Cluster: Understand decimal notation for fractions, and compare decimal fractions.

Make 4.NF.5 Graph PaperAll 28 4th Grade Math Standards

The Official Wording

Express a fraction with denominator 10 as an equivalent fraction with denominator 100, and use this technique to add two fractions with respective denominators 10 and 100. For example, express 3/10 as 30/100, and add 3/10 + 4/100 = 34/100.

Common Core State Standards, Grade 4, Number & Operations: Fractions · Read it at the source · Checked October 14, 2026

What 4.NF.5 Means in Plain English

Fourth graders rewrite tenths as hundredths: 7 tenths of a hundreds grid is 7 full columns, the same as 70 small squares, so 7/10 = 70/100. That lets them add across the two sizes: 7/10 + 25/100 = 70/100 + 25/100 = 95/100.

This is equivalent fractions (4.NF.1) with one special multiplier, 10, and it sets up decimals right away: 95/100 is written 0.95 (4.NF.6). In 5th grade, the same move lets students add decimals to hundredths, like 0.7 + 0.25 (5.NBT.7).

4.NF.5 I Can Statements

  • I can rewrite a number of tenths as hundredths, like 7/10 = 70/100.
  • I can show tenths and hundredths on a hundreds grid.
  • I can add a fraction in tenths to one in hundredths.

4.NF.5 Worked Example

Dimes and pennies, the tenths and hundredths of a dollar that students already carry around.

Problem

Ravi has 6 dimes. Kim has 15 pennies. Together, what fraction of a dollar do they have?

6 dimes and 15 pennies, as a fraction of a dollar
  1. A dime is one tenth of a dollar and a penny is one hundredth, so write each amount as a fraction of a dollar.6 dimes = 6/10, 15 pennies = 15/100
  2. Tenths and hundredths are different-sized pieces, so they cannot be added yet. Trade each dime for 10 pennies.6/10 = (10 × 6)/(10 × 10) = 60/100
  3. Now both amounts are in hundredths. Add the hundredths.60/100 + 15/100 = 75/100
  4. Seventy-five hundredths of a dollar is 75 cents.75/100 of a dollar = 75¢
Answer75/100 of a dollar, which is 75 cents

Check it: Shade a hundreds grid: 6 full columns of ten for the dimes, then 15 more squares for the pennies. That is 60 + 15 = 75 squares.

Common Mistakes with 4.NF.5

Adding straight across

6/10 + 15/100 = 21/110

Try this: Ask what size each piece is. Trade the tenths for hundredths first, so 6/10 becomes 60/100 and the pieces match.

Changing the bottom but not the top

6/10 + 15/100 = 6/100 + 15/100 = 21/100

Try this: Shade 6/10 on a hundreds grid: six whole columns, which is 60 small squares. Multiply the top by 10 along with the bottom.

Dropping a zero from the hundredths

15/100 = 15/10, so 6/10 + 15/10 = 21/10

Try this: Check the size: 15/10 is more than a whole dollar, but 15 pennies is not. Change the tenths into hundredths instead.

Where 4.NF.5 Fits

Comes Before3.NF.3Explain simple equivalences, like 1/2 = 2/4, with a model.4.NF.1Make equivalent fractions by multiplying top and bottom by the same number.
Alongside4.NF.6Write 75/100 as 0.75 and place it on a number line.4.MD.2Solve money word problems with simple fractions and decimals.
Comes Next5.NBT.7Add and subtract decimals to hundredths.5.NF.1Add fractions with any unlike denominators, not just 10 and 100.

Practice 4.NF.5

Graph Paper GeneratorFree ToolOutline 10 by 10 blocks of squares as one whole each: a column is a tenth, a square is a hundredth, and 6/10 + 15/100 gets shaded square by square.1 cm squaresOne pagePrint
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Math Worksheet GeneratorFree ToolSums like 3/10 + 52/100, with an answer key that shows the tenths rewritten as hundredths first.FractionsTenths and hundredthsAnswer key
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Quick Check

  1. 3/10 + 52/100
  2. Write 9/10 as hundredths.
  3. A snail crawls 4/10 of a meter, then 7/100 of a meter more. How far does it crawl in all?

4.NF.5: Other Names

4.NF.54.NF.C.5CCSS.MATH.CONTENT.4.NF.C.5

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.