n/2(n + 1) = 49½ x 100 = 4950
The sum of all odd numbers 1 through 99 is 9,801.
Their sum is 99.
99
It is instructive to note that you can rewrite 1+2+3+4....+99+100 as 1+100+2+99+3+98....+50+51 Then you can group each pair of numbers as (1+100)+(2+99)+(3+98)+...+(50+51) All of these couplets add up to 101, and there are 50 of them. Thus the sum of the first 100 whole numbers is 50x101. This can be calculated at 5,050.
43
99^2 == 9,801
9801 * The sum of the first two odd numbers (1+3) is 4, or 22 * The sum of the first three odd numbers (1+3+5) is 9, or 32 * The sum of the first four odd numbers (1+3+5+7) is 16, or 42 * ...and so on So the sum of the first 99 odd numbers, using the pattern above, would be 992 or 9801.
The sum of all odd numbers 1 through 99 is 9,801.
Their sum is 99.
100
4950
2500
-99
100
99
Do you mean:"What three consecutive numbers add up to 99?" If you do, then the numbers are 32, 33, 34.
First, you must add all five numbers. If you do so, you should get 390. Then, you divide the sum of the numbers (390) by the amount of numbers you have (5). 390 divided by 5 gives you 78.