Max Maths, Year 5, Try it, Multiplying by 25 mentally

In the Max Maths Year 5 curriculum, students are encouraged to develop their mental arithmetic skills, particularly when multiplying by 25. The 'Try it' section presents a straightforward method for performing this task without the need for long multiplication. For example, to find the product of 18 and 25, students first multiply 18 by 100, which is a simple task of adding two zeros to the number, resulting in 1800. The next step is to divide this answer by 4, which is the equivalent of finding a quarter of the number, and since 25 is a quarter of 100, this process effectively multiplies the original number by 25. The final answer is obtained after completing the division.

The 'Let’s Practise' section further reinforces this method by asking students to apply it to another problem, such as 14 multiplied by 25. Again, the process involves multiplying 14 by 100 to significantly increase the number, and then dividing by 4 to find one quarter of the result. This technique highlights the relationship between multiplying by 100 to enlarge a number and dividing by 4 to find a quarter, which is conceptually the same as multiplying by 25. Students can practice this method and consolidate their understanding by referring to the workbook pages provided in the curriculum.