We're not quite sure what the "2 digit numbers of 100" are.
Do you mean all the "2-digit numbers you say as you count to 100" ?
If that's it, then here's how to sum them:
There are 100 of them, minus (1 through 9, and 100) = 100 - 10 numbers = 90 numbers.
Make pairs of them . . .
10 + 99 = 109
11 + 98 = 109
12 + 97 = 109
13 + 96 = 109
14 + 95 = 109
.
.
etc.
There are 45 pairs, and every pair adds to 109.
So the sum of all 90 numbers is (45 x 109) = 4,905.
105 is the sum
Seven of them.
46
There are nine of them. They are:108117126135144153162171180
The sum of all palindromic numbers from 1001 to 9999 is 495000.
111 and 201
105 is the sum
105 is the sum
Seven of them.
46
The sum of all the integers between 100 and 999 is equal to 494450 - which also happens to be the answer to the sum 899 x 500 (which refers to the number of numbers multiplied by the mean number + 0.5).
There are 8 numbers between 100 and 200 (inclusive) that have a digit sum of 12, namely: 129, 138, 147, 156, 165, 174, 183, 192.
There are nine of them. They are:108117126135144153162171180
The sum of all palindromic numbers from 1001 to 9999 is 495000.
The sum of the all prime numbers from 1 to 100 is 1,161
what is the least possible sum of two 4-digit numbers?what is the least possible sum of two 4-digit numbers?
There are no 3-digit whole numbers whose digits sum to 3. The smallest 3-digit number is 100, and the largest is 999, but in neither case is the sum of the digits equal to 3.