Question

what is the sum of first natural number from 1 to 700

Answer 1

1+2+3+4+...........+700.. eq-1
By gauss law
Take all the terms in reverse in manner
700+699+698+697+............+4+3+2+1..eq-2
Now add eq-1 and eq-2
We get
701+701+701+........701+701..(700times)
We can write this as
700*701
Now divide it by 2
700*701/2
=350*701
=245350
That's the solution for sum of natural numbers from 1 to 700