This displays the Getting started on page 53 of the Student Resource Book.

• For each number students might identify the previous tens number as well as the next tens number, so that a can be made to addition (moving to the right on the number line), and subtraction (moving to the left on the number line).
• Discuss which facts are helpful for making tens numbers and encourage students to practise facts that make ten if they cannot easily recall them.

This shows a computer game screen which asks students to find the difference between two numbers by jumping through a tens number. They can either use addition or subtraction to solve the problem.

• Students can earn a bonus by identifying another way to find the difference. For example, Level 1 might also be solved by jumping 65 – 5 – 7 = 53; 53 + 7 + 5 = 65; or (without the bonus point) 53 + 2 = 55 and 55 + 10 = 65. 
• Teachers could give students the opportunity to share these different strategies with a partner and discuss which strategy was quicker or easier

This displays equations and gives students an opportunity to practise making a tidy number while justifying their decision to partition in a particular way.

• It is important that students are encouraged to listen and try to understand each other’s strategies and to appreciate that there is often more than one way to the correct answer. Sometimes one strategy may stand out as being quicker or easier than another, but other times it may be a matter of individual preference.

This displays an example of adding in parts through a ‘tens number’ to solve an addition problem.

• Students may be able to suggest several ways to partition. For example, using three ‘jumps’ as indicated on the numberline (38 + 10 = 48, then 48 + 2 = 50, and finally 50 + 3 = 53), or (38 + 2 = 40, then 40 + 10 = 50 and finally 50 + 3 = 53).
• Teachers may choose to use this opportunity to compare all of student’s alternative strategies and discuss which are more efficient. It is helpful to prompt students to look for strategies that use fewer steps or are quicker or easier to do mentally, to evaluate strategies or justify their decisions.

This displays a sheet with an example of partitioning through a tens number to solve two subtraction problems.

• This strategy subtracts the tens and ones in stages by jumping through a tens number.

• Students could use the diagrams on the sheet or other materials (such as unifix cubes), to explain to a partner how Max             solved the equations by subtracting in parts,
• It is important that students practise recording their thinking and are able to explain how they have partitioned the number to make solving the problem quicker or easier.

This displays a sheet with some addition and subtraction problems with two different tens strategies used to work each out. Students are asked which way they think is the most efficient.

The last page asks students which tens strategy they would use to work out the answer to three more problems. The strategies are named in a box.

• It could be a good idea to quickly revise each tens strategy.
• For the last page, you could divide students into groups and ask them to work out the answers to each problem first and then discuss the strategies used as a class.
• It is important that students practise recording their thinking, are able to explain how they have worked out their answer and say why they think their strategy is efficient.