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Year 2 - Maths

Explore the counting sequence for counting to 100 and beyond

Counting and representing the numbers 20 to 99

Unit Summary

In this unit pupils will explore the counting sequence for counting to 100 and beyond representing numbers from 20-99 in different ways including marking the position on a number line They will learn to represent 20-99 in the context of length.

Lesson Summary

You will learn to explore the counting sequence for counting to 100 and beyond.

Key Notes

  • There is set counting sequence for counting to 100 and beyond.
  • The patterns in the numbers make counting to 100 and beyond easier.
  • The tens digit in a two-digit number indicates which decade it belongs to.
  • The ones digit in two-digit number follows the pattern 1, 2, 3, 4, 5, 6, 7, 8, 9
  • We can count the numbers in two ways. This is called dual counting.

Vocabulary To Learn

  • Decade numbers: A set of ten numbers, all beginning with the same number of tens.
  • Digit: A single symbol used to make a numeral
  • Dual counting: Counting the same set of numbers in two different ways.

Common Mistakes To Avoid

  • Children may think counting stops at 100 or the regularity of the pattern does not extend past 100

3 Quick Questions (With Answers)

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

There is set counting sequence for counting to 100 and beyond. The patterns in the numbers make counting to 100 and beyond easier.

2. Use this key word in a maths sentence and explain it clearly. 'Decade numbers'

A set of ten numbers, all beginning with the same number of tens. Use this word when showing your method, then check your final answer is reasonable.

3. Spot and fix this common maths mistake.

Mistake: Children may think counting stops at 100 or the regularity of the pattern does not extend past 100. Correction: Count beyond 100 when rote counting, trailing off after 103 or 104 and discussing what would be next to make explicit that numbers do not 'end' at 10. Show numbers past 100 on equipment used.

More Lessons In This Unit

Browse all guides in the Year 2 Maths guide library.