13 of them: 349, 358, 367, 376, 384, 394, 439, 448, 457, 466, 475, 484, 493.
We have to consider 2 cases:
When the hundreds digit is 3, we want the sum of the tens and unit digit equal to 13. We have 4+9=5+8=6+7=13, which yield a total of 6 choices (two for each pair that adds to 13).
When the hundreds digit is 4, we want the sum of the tens and unit digit equal to 12. We have 3+9=4+8=5+7=6+6=12. The first three pairs give us 2 solutions, but the last only gives 1, so we have a total of 7 choices.
Therefore there are total of 6+7=13 integers.
There are none.
Counting all integers from 1 to 238 inclusive, there are 606 digits between these two numbers.
Two integers.
952 of them.
An infinite amount
There are 120 of them.
There are none.
Counting all integers from 1 to 238 inclusive, there are 606 digits between these two numbers.
There are 20.
How many
There are 125 of them.
Two integers.
Since the first integer of the 3-digit numbers must be 2, the sum of the second and the third digits would be 13.Since the largest digit is 9, the 3-digit numbers could be 249, 294, 258, 285, 267, and 276.Thus, there are 6 integers between 200 and 300 whose sum of their digits is 15.
9*9*8*7 = 4536
There are infinitely many. For example, consider, 45, 451, 4511, 45111, 451111 and so on.
952 of them.
An infinite amount