Partition Tree Subtracting from numbers with lots of zeros. This tool is based on a fascinating article written by Mark Wainwright in the Mathematical Association's Primary Mathematics magazine (Aut 2022). This technique for subtracting from numbers with lots of zeros was devised by his 9 year old student. Have fun! This game is © copyright 2023, J.Barrett, ictgames.com All Rights Reserved. Made using the and libraries.