20+19-18+17+16+15-14-13+……+4+3-2-1
问题描述:
20+19-18+17+16+15-14-13+……+4+3-2-1
答
(20-18)+(19-17)+(16-14)+(15-13)+(12-10)+(11-9)+(8-6)+(7-5)+(4-2)+(3-1)=20
20+19-18+17+16+15-14-13+……+4+3-2-1
(20-18)+(19-17)+(16-14)+(15-13)+(12-10)+(11-9)+(8-6)+(7-5)+(4-2)+(3-1)=20