Addition and Subtraction

Objectives

To add pairs of 2-digit numbers by partitioning or counting on.

Resources

Abacus Workbook 3 | 📄 Place value cards | Interactive place value link (Mathsframe) | 📄 Additions

Vocabulary

add | addition | tens | ones | partition

Today's Lesson

What to Get Ready

Print and cut out the 📄 Place value cards so that there are separate 2-digit and 1-digit numbers.

Introduction

Before you start the lesson, watch this Recap Video with your student.

Give your student the cut-out 📄 Place value cards and ask them to add 32 and 24.

Model this process using the interactive place value link.

PRACTISE - Interactive place value link (Mathsframe)

Move the tens together and ask:

How many 10s altogether?

Move the ones together and ask:

How many 1s altogether?

Record as follows:

32 + 24

= 30 + 20 + 2 + 4

= 50 + 6

= 56

Discuss how we can also count on in 10s and then 1s (start at 32; add 20 then 4): 32…42...52...53...54...55...56

Ask your student to help you to draft an empty number line jotting to help record this.

Point out that they will get the same answer whichever method they use, so they can choose whichever they prefer.

Write:

73 + 21

52 + 37

54 + 26

47 + 35.

Ask your student to work the additions out on paper, using either method: partitioning or counting on.

Discuss which method(s) your student chose and why: they might find that adding on 21 for example is very straightforward to do by counting on, whereas they may have preferred using partitioning to find 52 + 37 as counting on the 7 ones was a little trickier.

Some students may spot the 4 and 6 to make 10 in 54 and 26 and so preferred partitioning.

Model 47 + 35 using partitioning, to show what happens when the ones add to more than ten.

Main Activity

Ask your student to complete the 📄 Additions sheet, declaring the method they have used each time.

Workbook

To help your student consolidate their learning from today, please ask them to complete the activities on page 38 of Abacus Workbook 3.

Citations

[1] mathsframe.co.uk