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Answer to problem 8:

48 – 16 = 32

TEACHER NOTES:

“As students in the early grades work with complex tasks in a variety of contexts, they also build an understanding of operations on numbers. Appropriate contexts can arise through student-initiated activities, teacher created stories, and in many other ways. As students explain their written work, solutions, and mental processes, teachers gain insight into their students’ thinking.

An understanding of addition and subtraction can be generated when young students solve joining and take-away problems by directly modeling the situation or by using counting strategies, such as counting on or counting back (Carpenter and Moser, 1984). Students develop further understandings of addition when solving missing-addend problems that arise from stories or real situations. Further understandings of subtraction are conveyed by situations in which two collections need to be made equal or one collection needs to be made a desired size.”[1]