(1-2²)+3²-4²+5²-6²+7²-8²+9²-10²

问题描述:

(1-2²)+3²-4²+5²-6²+7²-8²+9²-10²

  原式=-(2^2-1)-(4^2-3^2)-(6^2-5^2)-(8^2-7^2)-(10^2-9^2)  =-(2+1)(2-1)-(4+3)(4-3)-(6+5)(6-5)-(8+7)(8-7)-(10+9)(10-9)  =-3*1-7*1-11*1-15*1-19^1=-3-7-11-15-19=-55