2.2 Written Strategies for Addition

Unit Objectives

• We are learning to explore and choose appropriate written addition strategies to solve addition problems.

Success Criteria

• I can use place value and the split strategy to solve addition problems.

• I can use place value and vertical addition to solve addition problems.

• I can choose a strategy to solve addition number and word problems.

Learning Objective

• To turn numbers around (commutative property) and split them to help us add. 

Success Criteria

• Explain that numbers can be added in any order (commutative property)

• Reorder an addition problem to make it easier to solve

• Split a number into parts that are easier to add

• Add the parts to find the total

What are some other ways we can rearrange the parts?

Is the answer still the same?

What way did you find easiest?

Reverse Split Strategy

Interactive Tool

For larger numbers, it can be easier to add the smaller place values first.

Guided Practice page 30

Let's mark Independent Practice.

Learning Objective

• We are learning to use the vertical algorithm to add numbers accurately, including when we need to trade (regroup) and when we do not.

Success Criteria

• Set out addition problems correctly using the vertical (column) algorithm

• Add digits in the correct place value columns (ones, tens, hundreds)

• Recognise when trading (regrouping) is needed

• Add without trading 

• Trade when required

Trade or No Trade

No trading: The total is less than 10, so we can write it straight down.

Trading: We have 10 or more, so we trade 10 ones for 1 ten.

Think of an example for each.
-turn and talk-

Roll two 10-sided dice, twice. Set up the numbers in column algorithm.

Trade or No Trade?

Let's solve. 

-REPEAT-

Let's add another die.

-REPEAT-

Let's have a go at using vertical algorithm for three-digit numbers.

Follow along to write notes to help you with your learning.

Share your notes with a partner.

Has your partner included:

🎯 trade or no trade rules

🎯 place value columns drawn neatly

🎯 addition symbol included

🎯 started on the right

Learning Objective

• We are learning to use the vertical algorithm to add numbers accurately, including when we need to trade (regroup) and when we do not.

Success Criteria

• Set out addition problems correctly using the vertical (column) algorithm

• Add digits in the correct place value columns (ones, tens, hundreds)

• Recognise when trading (regrouping) is needed

• Add without trading 

• Trade when required

1.  Have your board portrait.

2.  Set up the top half of your whiteboard with a 6 rectangle grid (2 rows of 3).

3.  Choose 6 different numbers from below and write one in each grid space.

Use the bottom half of your board for working out.

Write the equation I read out, and solve. 

✅ Tick the answer if it is in your grid.

🏁 First person to get a row of three wins.

Learning Objective

• We are learning to use inverse operations to solve addition and subtraction problems.

Success Criteria

• I can use inverse operations to solve missing number problems

An easy way to solve is to count on.

1. Count up in 10's

Start at 47: 57, 67, 77 (30)

2. Count up in 1's

77, 78, 79, 80, 81, 81 (5)

3. Add your 10's and 1's together

30 + 5 = 35