Addition and subtraction - Mixed addition and subtraction - Presentation

Lesson 20 of the Mixed Addition and Subtraction series presents a set of engaging activities designed to help students practise their arithmetic skills. The lesson starts with a discussion prompt, encouraging students to think of word problems that involve both adding and subtracting. This is followed by a series of activities where students are presented with practical scenarios requiring them to calculate the total number of items by combining addition and subtraction. For example, Leanna has 4 cookies, and Malachi has twice as many. Students are guided to determine how many cookies they have in total, using visual aids such as bar models to illustrate the quantities and relationships between the numbers.

Further activities continue to build on these skills, with varied situations such as Zach having 3 cookies and Rosie having twice as many, and Esin with bags of pears with different quantities in each. Students are asked to use the information provided to complete bar models and perform the necessary calculations to find the total number of items. The lesson emphasises the practical application of mixed addition and subtraction through relatable examples, reinforcing the concepts with visual representations and clear steps to solve each problem. As the lesson progresses, students are encouraged to work independently, spotting mistakes and completing calculations on their own, which fosters a deeper understanding of the mathematical principles involved.