Students can use this flowchart as a reference while subtracting three- or two-digit numbers. The flowchart takes students and teachers through the procedure of subtracting two- and three-digit numbers within 1,000. It is set up for subtraction across zeroes, with regrouping, and without regrouping.
I've used this chart to reinforce students' use of the subtraction procedure. I have students keep this resource to reference throughout the year, when they forget the steps or make mistakes!