I use the activity with my year 2 students but it can easily be adapted to suit other year groups. This resource is a maths investigation to practice addition with regrouping. There are 3 levels of challenge to meet the varying needs of the pupils. You will need a box of small building bricks or lego. I just pick out the pieces I need and put a small amount on each table. A small amount goes a surprisingly long way with this activity as their constructions are quite small. I usually take pictures of the structures so we can talk about the value of each during the plenary. You might also be interested in: https://www.tes.com/teaching-resource/3-open-ended-fraction-investigations-12058545