Doubling and halving - Teaching Presentation - Year 1

This presentation provides two days of teaching that cover the objectives:

• Doubling numbers.
• Halving numbers.

It includes starter activities, whole class teaching, group activities, practice sheets and mastery questions. It can be used on a variety of interactive whiteboards.

Day 1 Teaching
Explain that when we double a number we add the same amount again, e.g. 2 doubled is 2 + 2 = 4, 3 doubled is 3 + 3 = 6, etc. What is double 10? 10 + 10 = 20. Double 11? We double the 10, (20) and then double the 1 (2). Recombine these amounts to give a total of 22. Provide a visual representation to support visualisation, using base-10 equipment (e.g. Dienes cubes or number shapes such as NumiconTM) to model the partitioning, doubling and recombining steps. Repeat with 12, 13 and 14.

Day 2 Teaching
Explain that halving is sharing the number between two. Demonstrate by sharing four sweets between two children. Repeat with other even numbers up to 20. Odd numbers are harder to share as there is always one left over. Display a bar model to show double 8 is 16. Use this to halve 16. As last time, providing a visual representation using base-10 equipment will support partitioning, halving and recombining.

This teaching is part of Hamilton’s Year 1 Multiplcation, Division and Fractions block. Each Hamilton maths block contains a complete set of planning and resources to teach a term’s worth of objectives for one of the National Curriculum for England’s maths areas.