Question 350524: How many whole numbers less than 500 have seven as the sum of their digits?
Answer by ewatrrr(24785)   (Show Source):
You can put this solution on YOUR website! Hi,
*Note: Let htd represent the numbers less that 500.
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Question states:
h + t + d = 7
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Starting with the 400s
4 + t + d = 7
t + d = 3 (0,1,2, 3 are the possible values of t)
403, 412, 421,430
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300s
3 + t + d = 7
t + d = 4 (0,1,2,3,4 are the possible values of t)
304, 313, 323, 331, 340
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Repeat process for the 200s, the 100s and when h =0 (the 2-digit numbers)
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