Grasp Maths

Year 3

Count up and down in tenths; recognise that tenths arise from dividing an object into 10 equal parts

Count in tenths and connect tenths to 10 equal parts of a whole.

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Lesson overview

Number - fractions

A tenth is one of 10 equal parts. We can count in tenths on a fraction strip or a number line: one tenth, two tenths, three tenths and so on until ten tenths, which makes one whole.

One whole split into tenths

Ten equal parts make tenths.

10 tenths make 1 whole.

Each part must be equal to be a tenth.

Count up in tenths

We can count 110\frac{1}{10}, 210\frac{2}{10}, 310\frac{3}{10} and so on.

The numerator increases by 1 each time.

Count down in tenths

We can also count backwards from one whole.

The numerator decreases by 1 each time.

Worked example

What comes after 610\frac{6}{10} when we count in tenths?

  1. Count in tenths by increasing the numerator by 1.
  2. 610\frac{6}{10} is followed by 710\frac{7}{10}.
  3. The denominator stays the same because the whole is still split into 10 equal parts.
  4. So the next fraction is 710\frac{7}{10}.

Try it

Keep the denominator the same and count the numerator up or down by one each time.

Question 1

What comes after 310\frac{3}{10}?

Question 2

How many equal parts make tenths?

Whole1
Equal parts10
Question 3

Write the numerator in 710\frac{7}{10}.

Question 4

What is 1010\frac{10}{10} equal to?

Question 5

Which sequence counts down in tenths?

Common mistakes

Watch for these when working through the lesson.

  • Changing the denominator while counting in tenths.
  • Forgetting that the parts must be equal.
  • Thinking ten tenths is bigger than one whole.

Related topics

These ideas fit closely with this lesson.

  • Recognise, find and write fractions of a discrete set of objects.
  • Recognise and show, using diagrams, equivalent fractions with small denominators.

Practice next

Independent practice will plug in here

This lesson introduces the idea clearly first. Deeper adaptive practice can sit here later.