Addition and subtraction - Subtract a one-digit number from a three-digit number crossing 10 - Presentation

In a comprehensive lesson plan aimed at enhancing subtraction skills, students are introduced to the concept of subtracting a one-digit number from a three-digit number, particularly when this involves crossing 10. The lesson begins with a discussion, prompting students to think about whether they are moving forwards or backwards on the number line and if there are sufficient ones to subtract from. They explore the possibility of exchanging a ten for ten ones to facilitate subtraction. The use of physical equipment, such as cubes, is encouraged to visually represent and solve the subtraction problems. This method helps to reinforce the understanding of the subtraction process and the concept of 'borrowing' or regrouping when necessary.

Further into the lesson, various activities are presented to solidify the students' grasp of the topic. These activities include solving subtraction problems using equipment, applying the part-whole model to aid in calculations, and interpreting subtraction in the context of word problems. For example, students might be tasked with determining the points Hazel Class finished with when they earned 9 points less than Oak Class's 827. The lesson plan also encourages critical thinking by asking students to discuss and reflect on the efficiency of different subtraction methods. Additionally, independent work is designed to challenge students to use counters, number lines, and their own reasoning to solve subtraction problems and explain their methods, fostering a deeper understanding of the mathematical concepts at play.