Here are the ways that four students thought about some subtraction facts. For each student, describe where each number in his or her thinking came from and why the strategy works. Then identify the basic fact strategy for subtraction being used by each of these students. (a) 14 - 9: Dale: "Nine and 1 more is 10, and then 4 more gets me to 14, so 1 and 4 is 5." (b) 15 - 7: Audrey: "I know that 7 and 7 is 14, and 1 more makes 15, so 1 plus 7 is 8." (c) 13 - 5: Jose: "First I took off 3 to get to 10, and then minus 2 more gets me to 8." (d) 15 - 8: Tamara: "I thought about how far it is from 8 to 15. It takes me 2 to get to 10, and then 5 more to get to 15, so 2 and 5 is 7."