Infinitely many. 45 + 45, 46 + 44, 47 + 43, ... , 98 + 1, 99 + 0, 100 + (-1), 101 + (-2) and so on and on and on. Without an end in sight.
100
2500
Do you mean:"What three consecutive numbers add up to 99?" If you do, then the numbers are 32, 33, 34.
The numbers are 97, and 99.
49 of them.
4950. If you add the pairs (1+99)+(2+98)... You get 100 for each pair. There are 49 pairs, and the 50 stands alone. So 4900 +50 is 4950.
Infinitely many. 45 + 45, 46 + 44, 47 + 43, ... , 98 + 1, 99 + 0, 100 + (-1), 101 + (-2) and so on and on and on. Without an end in sight.
The sum of all odd numbers 1 through 99 is 9,801.
100
Well, darling, the sum of the first 99 odd numbers is 9801. You see, you take the last odd number, which is 197, multiply it by the total number of odd numbers (which is 99), and divide by 2. Voila! Math magic at its finest.
4950
You need to add all the numbers from 10 to 99. You can do that quickly with the formula for an arithmetic series.
2500
-99
100
99