These are three great worksheets for practicing the subtraction strategies: subtracting 0, subtracting 1, and counting down on a number line. At the top is a description of the "What, Why, and How". These are three questions students are often asked during lessons: What are you learning about? Why is this important? How are you being assessed? This helps communicate the objectives and outcomes of the lesson to the students. An extension question is included for each one to help determine which students are understanding the content on a deeper level. This could also be used as a math assessment.