In this unit, children first recap on their understanding of partitioning, and then use this method to solve addition and subtraction number sentences involving two-digit numbers. Next, they apply this knowledge to addition number sentences with more than two two-digit numbers. Children then learn how to solve number puzzles and investigate mathematical statements through reasoning and deduction.

Each lesson comes with a detailed plan, an engaging slide show for the teaching input, as well as differentiated worksheets and activity ideas!

Adding using the Partitioning Method

In this first lesson, children will recap on their understanding of partitioning, and then use this knowledge to help them solve addition number sentences involving two-digit numbers. Children will be encouraged to show the steps of their working out in their independent activities.

Subtracting using the Partitioning Method

Children will recap on how to use partitioning to help them solve addition number sentences, and then discuss how to use this method to solve subtraction number sentences. Children can work in pairs to create number sentences for each other to solve, or in the alternative activity, challenge themselves to complete the Subtraction Grid to a given time limit!

Adding Several Numbers

Now that children are familiar with using the partitioning method, they will apply what they have learnt so far to help them solve number sentences that require the addition of more than two two-digit numbers. They will practise this skill by working independently, or in pairs, to solve different fun challenges!

Solving Puzzles

Children will use their addition and subtraction skills and their knowledge of partitioning to solve number puzzles. They will learn how to reason about answers, and narrow down possible options in order to find the final answer.

Investigating Statements

In this final lesson, children will find out what a mathematical statement is. As a class, they will learn how to investigate a statement, and decide whether it is true or false. Children then have the opportunity to investigate statements independently or in pairs, depending on the activity chosen.