I just think all numbers must be used to reach the total period. Some of the answers are easy if you can just use a few. Trying to make them all work is more challenging. *shrug* You all can do what you want but my future answers I'm going to use all the numbers. So there.
2, 3, 5, 8, 13, 21 ?= 987
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The count of numbers used might not work because if you got it with say 4 numbers how long would you wait to know it was your turn?