Leon has 306 boxes to move. He can carry 9 at a time. How many trips does he need to make? |
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Student: Ten times nine equals ninety. Ninety and ninety makes one hundred and eighty, and ninety more makes two hundred and seventy. That's thirty times nine. Then you keep adding 9 more on ... 279, 288, 297, 306. Thirty and 4 more makes thirty-four. |
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Students at the Advanced Additive stage are learning to choose appropriately from a repertoire of part-whole strategies. They see numbers as whole units in themselves but also understand that “nested” within these units is a range of possibilities for subdivision and recombining. |
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