(1+1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)×(1/2+1
(1+1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)×(1/2+1
1×2/1+2×3/1+3×4/1+4×5/1+5×6/1巧算
如何证明1+1/2+1/3+1/4+.+1/1000
简算(1+1÷2+1÷3+1÷4)×(1÷2+1÷3+1÷4+1÷5)-(1+1÷2+1÷3+1÷4+1÷5)×(1÷2
(1+1×3/1)(1+2×4/1)(1+3×5/1)……(1+99×101/1)
66666×666666分之1+2+3+4+5+6+5+4+3+2+1简算
(2+4+6+.+98+100)-(1+3+5+.+97+99)
1.(2+4+6+.1984+1986+1988)-(1+3+5+.+1985+1987)=?
简算:(1+1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)×(1/
1/1×2+1/2×3+1/3×4+1/4×5+……+1/39×40怎么计算?用简便计算方法!
计算1/1×2)+1/(2×3)+1/(3×4)+1/(4×5)+.+1/(42×43)=?
1/1×2×3+1/2×3×4+1/3×4×5+1/4×5×6+1/5×6×7