Number & Algebra
Chapter 4 | Adding and subtracting by choosing a strategy
Teacher Resource Sheets
Getting Started
The beach market (Getting started 4)
(You could use this sheet before starting the chapter to discuss the importance of choosing an 'efficient' strategy before beginning to calculate.)
This displays the Getting started on page 97 of the student book.
- Teachers could use this link to encourage ‘risk taking’ and exploration of different strategies for the same problem.
- Informing students that mathematicians often use a different strategy to ‘check’ or justify an answer provides a purpose for finding the answer in several different ways.
- This activity provides an opportunity to ensure that students understand the concept of ’efficiency’. Many students find the idea of a strategy being quicker (for example because there are fewer calculations or jumps), or easier (because facts are known or because tens numbers are used) is a helpful way to make sense of this.
Adding by choosing a strategy
The beach store (Teacher Resource Sheet 14)
(You could use this sheet in conjunction with Activity 1, page 100 of the Student Resource Book.)
This sheet can be used by teachers as a focus for discussion or to remind students of three strategies they might choose between when solving addition problems.
- It can be quite challenging for students to explain why one strategy is more efficient than another. It will be helpful if students practise this with a partner. You may like to listen for good explanations and share these ‘models’ with the rest of the class later.
Subtracting by choosing a strategy
How much change? (Teacher Resource Sheet 15)
(You could use this sheet in conjunction with Activity 2, page 102 of the Student Resource Book.)
This sheet can be used by teachers as a focus for discussion or to remind students of two subtraction strategies they might choose between to find the difference between the cost of an item and the amount paid.
- With the increasing use of ’swipe’ cards, receiving change is a situation that may be unfamiliar to some students. This sheet provides an opportunity to demonstrate how shop assistants might count from the cost of the item to the value of the amount paid. Students could model this scenario with ’play money’ alongside a number line to connect this real-life experience with a number line strategy.
Adding and subtracting by choosing a strategy?
Do I have to add or subtract? (Teacher Resource Sheet 16)
(You could use this sheet after Activity 3, page 104 of the Student Resource Book.)
This displays a price board from a beach shop. Students are asked to calculate how much the characters have spent, to compare the prices of items and to decide what could be bought with a sum of money.
- Students could work together using play money or other place value materials to help them justify their choices and solve these problems.
