Math hlp!!!!!!!?

well im in this advance math cl and i cant figure this problem she asked us to add all the numbers from 1-100 and get the answers and see if there is a pattern/strategy 2 do it easily but i tried adding on the calculator but i dont get an answer my calculator broke 1+2+3+4+5+6+7+8+9+10............,,,and so on so PLZ HHeeLLpp