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Year 5 - Maths

Describe and represent tenths as a decimal number

Understand tenths as part of a whole, represent and calculate mentally

Unit Summary

In this unit pupils will describe, represent and order tenths as a decimal fraction. They will round a decimal number with tenths to the nearest whole number and calculate mentally with decimal numbers including tenths.

Lesson Summary

You will learn to describe and represent tenths as a decimal number.

Key Notes

  • If a digit is moved one place value column to the right it becomes one tenth the size.
  • One tenth is one tenth the size of one whole.
  • Tenths are recorded in the column to the right of the decimal point so one tenth is 0.1
  • The decimal point separates whole numbers from numbers with a decimal fraction part.

Vocabulary To Learn

  • one tenth the size: When a whole is divided into ten equal parts, we can say one of those parts is one tenth the size of the whole.
  • tenths column: The tenths column places the number of tenths a given number has.
  • decimal point: A decimal point is a small dot used in a number to separate the whole number from the fractional part.

Common Mistakes To Avoid

  • Pupils put a digit in the ones column instead of the tenths column to represent a number of tenths.

3 Quick Questions (With Answers)

1. Solve this in steps: explain the method from this lesson and why each step matters.

If a digit is moved one place value column to the right it becomes one tenth the size. One tenth is one tenth the size of one whole.

2. Use this key word in a maths sentence and explain it clearly. 'one tenth the size'

When a whole is divided into ten equal parts, we can say one of those parts is one tenth the size of the whole. Use this word when showing your method, then check your final answer is reasonable.

3. Spot and fix this common maths mistake.

Mistake: Pupils put a digit in the ones column instead of the tenths column to represent a number of tenths. Correction: Continue to ask what each digit that has been recorded represents, linking back to the place value chart and the role of the decimal point.

More Lessons In This Unit

Browse all guides in the Year 5 Maths guide library.