Final answer:
The strategy mentioned by the student, starting with 15 cubes and subtracting 2 to get 13, is not the make-ten strategy, as it does not involve an intermediate step that rearranges the numbers to make ten.
Step-by-step explanation:
The student's question involves finding out whether the make-ten strategy is being used in the statement: "I started with 10 cubes and 5 cubes—that is 15 cubes—and then I took away the extra 2 cubes and got 13 cubes." The make-ten strategy is a mathematical approach typically used for addition and subtraction within 20, where you make ten as a helpful step and then adjust accordingly to find the final answer. In this case, however, the strategy described is not a make-ten strategy. Here, the student starts with 15 cubes (10 + 5) and then directly subtracts 2, without any intermediate step that involves making ten.
A make-ten strategy would involve an intermediate step such as using the 10 and an additional 3 from the 5 to make 13 directly, rather than starting at 15 and subtracting 2.