These four worksheets are aimed at giving children practice at subtracting multiples of ten from 100. The aim of this is that they learn the answers off by heart, so they no longer have to count on or back. As there only a short number of possibilities it is important for children to know these pairs of numbers which make 100: 10 and 90 20 and 80 30 and 70 40 and 60 50 and 50. Knowing these makes it much easier to subtract any 2-digit number 'in your head'. Subtracting multiples of 10 from 100