Mathematical Reasoning Investigation: Year 3/4 Lesson (Addition, 100 Square and Multiples)

I originally designed this for a 1-hour interview lesson, as I was asked to teach reasoning/problem solving, with a mixed Year 3/4 class - I was offered the job!

Starter: chn find all the numbers you can make between 1 and 100, by adding 5 (using a 100 square to leap frog). Then, discuss how we can identify ‘multiples’ of 5 (e.g. the final digit in the number always ends in a 0 or a 5).

During the main part of this investigation, students will learn to work systematically, as they will be investigating how many numbers between 1 and 100 (1 and 50 for Year 3s) you can make by adding only 3 and/or 5.

You can then extend the investigation (up level) using the suggested inquiry questions.