Addition and Subtraction

Objectives

To know pairs to 10, and then to 7, 8 and 9.

Resources

Abacus Workbook 1 | Camera

Vocabulary

balance | sum | total | equal

Today's Lesson

Assignment

This lesson works towards Assignment 1. Please access the assignment for details about what you will need to submit to your student's Wolsey Hall tutor.

Introduction

Show your student the Interactive number balance.

EXPLORE - Interactive number balance (MathZone)

Demonstrate how to click and drag the numbers as ‘weights’ to both sides of the balance.

Give your student time to play with and explore the balance and ask them to tell you what they have discovered after they have finished using it.

They should be able to tell you that a larger number is ‘heavier’, so the same number must be on both sides for the scales to balance.

Put on a 6 and 4 on one side of the scales. Challenge your student to balance the scales using only one number.

They should realise that the number needed is 10.

If they find this hard at first, show them that because 6 + 4 = 10, then 6 + 4 should weigh the same as 10.

Repeat with other examples, for example: 7 + 3, 2 + 1, 5 + 2 (all within totals of 10).

Balance a 9 and 1 on one side. Ask your student to balance exactly two numbers on the other side, but they must not be 9 or 1.

If they struggle with this, say, ‘Because 9 and 1 total 10, we must find another two numbers which total 10 for the other side. Which other numbers do you know that total 10?’

Repeat the above task with different pairs to make 10. Record the number sentences, for example: 6 + 4 = 7 + 3; 2 + 8 = 9 + 1.

Explain that these are balancing number sentences: two number sentences which have the same total.

This time hang weights on 7 and 3 on the left, and 8 on the right.

Record 7 + 3 = 8 + □.

Where shall we hang a weight this time to balance?

Repeat with other pairs to 10, and then pairs to 8 on each side.

Main Activity

Challenge your student to write down their own balancing number sentences for 10. Remind them that this means two number sentences which both have the same total. For example: 8 + 2 = 9 + 1

Discuss each one and agree if it balances or not. Then test them using the Interactive number balance.

EXPLORE - Interactive number balance (MathZone)

Now ask your student to create their own balancing number sentences which each have a total of 7. For example: 5 + 2 = 4 + 3.

Discuss each one and agree if it balances or not. Then test them using the Interactive number balance.

Now ask your student to create their own balancing number sentences which each have a total of 7. For example: 5 + 2 = 4 + 3

Discuss each one and agree if it balances or not. Then test using the Interactive number balance.

Repeat process again to create balances with 8 on each side and with 9 on each side.

Film your student completing the activity, asking them some of these key questions as they work:

How did/do you make the scales balance?
What would happen if I put a 9 and 1 on one side? How would you make it balance with two numbers on the other side?
Can you hang four numbers on the scales, two on each side, to make them balance?
(Harder) Can you hang five numbers on the scales, two on one side and three on another, to make them balance?

Please note that the video should be short (no more than 2 minutes) and does not need to be a ‘polished’ video by any means. Its purpose is to give you and your student's Wolsey Hall tutor an idea of what they need to support their next steps in learning.

Extra Challenge

Your student should make additions with three numbers to make 10. Can they make five different ones?

Workbook

To help your student consolidate their learning from today, please ask them to complete the activities on pages 8 and 9 of Abacus Workbook 1.

Citations

[1] mathszone.co.uk