Fraction Classroom
Decimal explanations

Grade 5 · Read, model and practise

Regroup a tenth when subtracting hundredths

Exchange one tenth for ten hundredths while preserving the value of the starting amount.

Try the practice questions

Start with this question

How do you subtract 0.27 from 0.6?

The key idea: Write 0.60 as five tenths and ten hundredths. Remove two tenths and seven hundredths to leave three tenths and three hundredths: 0.33.

Make the idea visible

Rows: start, renamed start, amount removed, amount remaining. The 10 shows a temporary count of hundredths.OnesTenthsHundredths0600510027033
Rows: start, renamed start, amount removed, amount remaining. The 10 shows a temporary count of hundredths.
  1. Estimate the result: 0.6 minus a little less than 0.3 should be a little more than 0.3.
  2. Name 0.60 as six tenths. Exchange one tenth for ten hundredths: five tenths and ten hundredths still total 0.60.
  3. Remove seven hundredths from the ten hundredths, then two tenths from the five tenths.
  4. Record 0.33 and check by addition: 0.33 + 0.27 = 0.60. The check confirms the original amount is recovered.

A useful error to discuss

A learner might say: Subtract the smaller digit from the larger digit in each column.

The subtraction removes 0.27 from 0.60; it does not independently choose a direction for each column. When there are too few hundredths to remove, exchange a tenth.

Practise, then check

Try the first three questions with the model. Try the final check without help. A correct value is a starting point: explain how your units or drawing support it.

Practice 1

Answer & reasoning

0.44 · Rename 0.80 as 7 tenths and 10 hundredths, then subtract.

Practice 2

Answer & reasoning

0.55 · One whole is 100 hundredths; 100 − 45 = 55 hundredths.

Practice 3

Answer & reasoning

0.55 · Exchange one tenth; 13 hundredths minus 8 hundredths leaves 5.

Independent check

Answer & reasoning

0.73 · Use 1.20, regroup across the needed places and check 0.73 + 0.47 = 1.20.

Explain a new situation

Explain why changing 0.60 into 0.510 is not a correct way to record five tenths and ten hundredths.

Discuss the explanation

0.510 means five tenths, one hundredth and zero thousandths. Five tenths plus ten hundredths is 0.60; the temporary count 10 must stay in the hundredths column.

Materials for your group

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Choose the next step

If exchanges change the total, model the original amount with tenths and hundredths. If secure, subtract from one whole and explain both exchanges.

Open a related complete lesson →

Original Fraction Classroom examples and explanations. Curriculum reference: CCSS 5.NBT.B.7. Grade alignment describes the intended topic; it is not an endorsement or evidence of classroom results.

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