Max Maths, Year 4, Learn together, Mental multiplication (1)

In a Year 4 mathematics lesson focusing on mental multiplication, students are encouraged to develop their mental arithmetic skills, specifically in doubling numbers. The 'Let’s Learn Together' section provides clear steps to mentally calculate the double of two-digit numbers. For example, to double the number 67, students are guided to first double the tens place, which means multiplying 60 by 2 to get 120. Then, they double the ones place, multiplying 7 by 2 to get 14. By adding these two results together, 120 plus 14, they find that the double of 67 is 134. This method breaks down the process into simple steps that make mental calculation more accessible.

The lesson continues with the technique applied to larger numbers, such as doubling 460. The number 460 is seen as 46 tens, or 46 × 10. Students are instructed to first double the number 46 by doubling the tens (40 × 2 = 80) and then the ones (6 × 2 = 12), before combining these to get 92. To find the double of the original number, 460, they then multiply 92 by 10, resulting in 920. This step-by-step approach not only simplifies the process of doubling larger numbers but also reinforces the understanding of place value and the distributive property of multiplication over addition.