The sum of a series of numbers is calculated by adding the first one to the last one, multiplying by the number of numbers, and then dividing by 2.
For the series 50 to 151, there are 102 numbers (151 - 50 + 1). Since there is an even number of consecutive numbers, exactly half of
them are even and half are odd, so there are 51 even numbers and 51 odd numbers.
For the sum of the even numbers, the first is 50 and the last is 150, so the sum is (50 + 150) times 51 and the whole thing divided by 2.
For the sum of the odd numbers, the first is 51 and the last is 151, so the sum is (51 + 151) times 51 and the whole thing divided by 2.
Do your own arithmetic.
John
My calculator said it, I believe it, that settles it
