Answer:
Step-by-step explanation:
Use the formula Sum = (a + L)*n/2
The tricky part is n. That's the number of terms between 1 and 99 inclusive.
n = 99 -1 + 1 = 99
n = 99
a = 1
L = 99
Sum = (1 + 99)*99 / 2
Sum = (100)*99/2
Sum = 4950
