1/10*12+1/12*14+1/14*16+1/16*18=?快,

1/10*11+1/11*12+1/12*13+1/13*14+1/14*15等于? 1+10+11+12+13+14+15 10*12/1+12*14/1+14*16/1+16*18/1怎么算 简便计算10*1/12+12*1/14+14*1/16+16*1/18=? 1/10*12+1/12*14+1/14*16+1/16*18=?快, 1/10*11+1/11*12+1/12*13+1/13*14+1/14*15等于?我看不懂 |1/11-1/12|+|1/12-1/13|+|1/13-1/14+|1/14-1/15| 2/8*10+2/10*12+2/12*14+2/14*16 =1/16 怎么简算的要思考过程为神马2/8*10+2/10*12+2/12*14+2/14*16 =1/8-1/10+1/10-1/12+1/12-1/14+1/14-1/16 速度在线等 (1/10*12 +1)(1/11*13 +1)(1/12*14 +1).(1/20*22 +1)平方差公式应用 14x+(14-3)(1/12-x)=1 1/2*4+1/4*6+1/6*8+1/8*10+1/10*12+1/12*14+1/14*16 2/8乘1/10+2/10乘1/12+2/12乘1/14+2/14乘1/16+2/12乘1/14+2/14乘1/16 1+1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+19+15+14+15+12+14+1 等于多少? 请解答奥数题简便法.1/5+1/10+1/20+-----+1/160 2/10*12+2/12*14*+2/14*16*+2/16*18+1/18 (12分之1+14分之5)X12 11 12 13 14 1要理由 -1/10*11+1/11*12+1/12*13+1/13*14+···1/19*20的值 1/(x+10)(x+11)+1/(x+11)(x+12)+1/(x+12)(x+13)+1/x13=1/14