Question 915392: My sum is between 5 and 10. I am a double plus one. Who could I be?
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! Are we talking about the sum of the digits of a number?
Is that a 2-digit number? A 3-digit number?
IF we are talking about a 2-digit number,
whose sum of digits is between 5 and 10 (including 5 and 10),
and the number is a double plus 1 (meaning an odd number),
there are many possibilities.
Among odd 2-digit numbers ending in 1,
the numbers whose sum of digits is 5, 6, 7, 8, 9, or 10 are:
41, 51, 61, 71, 81, and 91.
Among odd 2-digit numbers ending in 3,
the numbers whose sum of digits is 5, 6, 7, 8, 9, or 10 are:
23, 43, 53, 63, and 73.
Among odd 2-digit numbers ending in 5,
the numbers whose sum of digits is 6, 7, 8, 9, or 10 are:
15, 25, 35, 45, and 55 (and there is none with 2 digits adding to 5).
Among odd 2-digit numbers ending in 7,
the numbers whose sum of digits is 8, 9, or 10 are:
17, 27, and 37.
Finally, among odd 2-digit numbers ending in 9,
the only numbers whose sum of digits is between 5 and 10 is
19.
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