A demonstration of how to subtract 11 from a two-digit number by taking away 10 before adjusting the answer by 1. Two characters at a launderette take 11 black socks from a basket containing 34 socks. The socks are put into separate washing machines. The characters subtract 11 from 34 by taking away 10 before adjusting the answer by 1.
Demonstrate how the number in the tens column goes down one and the number in the units column goes down one also, because one ten and one unit is eleven. Give the children some more numbers to rehearse and point out the tens column and the units column each time. What is 53 - 11? what is 46 - 11? and so on.