Question

What is the difference between the sum of the first 200 positive multiples of three and the sum of the first 200 positive even integers?

Answer 1

3*(2+3+4+...)-2(2+3+4+...)=2+3+4+....

so what is the sum of those 200 numbers?
PS, there can be some dispute on what positive multiple means (does in inclued times 1?)