Numbers can be combined in different ways to help solve problems when adding or taking away.  

We will use combinations of different numbers to solve addition problems. These numbers can be added in a variety of ways to arrive at the same answer.

Display Resource 9: Sums investigations and say that these 5 numbers (5, 6, 9, 12 and 14) will be hidden in a bag. On each turn, 2 numbers will be drawn out.

Students work with a partner to find the total of the 2 numbers. They can use ten-frames, counters and whiteboards to find their solution. Encourage students to use the language of ‘part’ and ‘whole’ as they work on their solutions.

Draw students’ attention to the range of strategies used. Ask:

Did another group use the same strategy as you to find the solution?

• Is there a strategy that you hadn’t thought of using?

• Is there a strategy that you think is the most helpful to find the solution?

• Is there a new strategy you might like to try with your partner?

Compare the range of strategies used. Ask:

• Did you use the same strategy as before with your partner, or did you try something different?

• Did another group use the same strategy as you to find the solution?

• Is there a strategy that you hadn’t thought of using?

• Did you notice any patterns?

• Is there a strategy that you think is the most helpful to find the solution?

• Is there a new strategy you might like to try with your partner?

Tell students that Nat has safely made it back from the planet Vuv. Ask the class:

• What were some of the ways you and your partner found solutions to the problem? (Prompt any students who used effective strategies to share these with the class).

• As you were working with your partner, did you discover a more useful strategy? What was it?

• Of all the strategies, which did you think was the most efficient? Why?

• Did you notice any patterns during this activity?

• Is there anything that you are still wondering about this activity?

As a class, compare the different ways the class used to solve the same problem. Highlight to students that mathematicians can solve the same problem in different ways.

Remind students that the lesson was about finding different ways of solving the same problem.

Ask students to think back to the strategy they used to solve the very first problem. For example, ask if they were still using the same strategy at the end of the lesson, or if had they learnt some new ways.

Invite students to share the strategy they found the most helpful, asking questions such as:

• Can you show us how you used your strategy to solve the problem?

• Why did you find this strategy, or these visuals, the most useful?

Draw students’ attention to the total number of different strategies students shared during the lesson.