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.
There are 120 of them.
There are 20.
How many
There are 125 of them.
There are infinitely many. For example, consider, 45, 451, 4511, 45111, 451111 and so on.
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.
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
Five. All nonzero integers are significant and zeros in between significant digits are significant.