Question

find the sum of all even numbers 101to999?

Answer 1

Hi friend,

Sum of first 'n' even integers = n(n+1)

sum of all even intergers between 101 and 999

= Sum of all even integers between 1 and 9999- sum of all even integers between 1 and 101

= 9999(9999+1) - 101(101+1)

= 9999(10000)-101(102)

=99990000-10302=99979698

HOPE THIS HELPS YOU:-))