Max Maths, Year 3, Learn together, Multiplying by 10 and doubling numbers mentally (3)

In a Year 3 mathematics lesson, students learn to mentally multiply by 10 and double numbers. Toby presents a practical example, stating he has 132 stamps, and poses the question of how many stamps Han would have if he has double the amount. The aim is for students to calculate this mentally, using their understanding of place value and mental arithmetic to find the answer.

The process begins by breaking down the number 132 into its constituent place values: 1 hundred, 3 tens, and 2 ones (132 = 100 + 30 + 2). This decomposition of the number into hundreds, tens, and ones makes it easier for students to visualise and mentally double each part separately. By doubling each value—100 becomes 200, 30 becomes 60, and 2 becomes 4—students can then recombine these doubled figures (200 + 60 + 4) to find the total number of stamps Han has, which is 264. This method demonstrates a clear and straightforward strategy for doubling numbers, reinforcing the concept that 132 doubled (132 + 132) is the same as 132 multiplied by 2 (132 × 2).