(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8=?

问题描述:

(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8=?

一共 (49-1)÷3+1=48÷3+1=17项(49-1/8)x1/8+(46-1/8)x1/8+(43-1/8)x1/8+.+(1-1/8)x1/8=49x18+46x1/8+...1x1/8-1/8x1/8x17=1/8x(49+1)x17÷2-17/64=850/16-17/64=3400/64-17/64=3383/64有13项怎么是13项,是17项你列一下你对的