Three Strategies for Opening Curriculum Spaces

Imagine the following scenario: A third-grade teacher opens the teaching guide for her district-mandated textbook to a multidigit subtraction lesson. The lesson shows the standard algorithm for subtraction, using the problem 377 – 187 = ? This example is followed by ten practice problems and, at the end of the lesson, two word problems. Reflecting on her students’ participation in a mental math routine earlier in the week, the teacher knows that her students can think about these problems in at least three other ways (see table 1). She also knows that, by the end of the lesson, most of her students will assume (correctly) that the word problems involve subtraction situations and will automatically apply the standard algorithm to solve those problems.