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Fraction Classroom · 2.2.0 · Student pages

Regroup a tenth when subtracting hundredths

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

Anonymous group code: __________   Date: __________

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.

Discuss the opening question

start. How do you subtract 0.27 from 0.6?

Work through the explanation

example. How do you subtract 0.27 from 0.6?

  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.

Worked example: Write 0.60 as five tenths and ten hundredths. Remove two tenths and seven hundredths to leave three tenths and three hundredths: 0.33.

Practise, then check independently

Use p1–p3 for practice. Try e1 without help. Show how your place-value units or model support the result.

p1. Calculate 0.8 − 0.36.

p2. Calculate 1.00 − 0.45.

p3. Calculate 0.73 − 0.18.

e1. Calculate 1.2 − 0.47.

Explain a new situation

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