5/1:8/1:20/1:30/1 = 24:15:6:4

5/1:8/1:20/1:30/1 = 24:15:6:4 (8^80)*(1/8^20)*(1/8^30)=? 1/2+1/6+1/12+1/20+1/30=简算13/5*8*8/13*125简算 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9=1-1/9=8/9为什么呢?写出解析. 1/20*(*-5)+1/30*(*-4)=1怎么解 1/2*5+1/5*8+1/8*11+1/11*14+.+1/17*20=? 1/2 - 1/6 - 1/12 - 1/20 - 1/30 - 1/42=?1/2+1/4+1/8+1/16+1/32+1/64=? 1/2+1/6+1/12+1/20+1/30+1/42+1/56=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8=1-1/8=7/8这一步=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8怎么会得到这步=1-1/8 1/2+1/6+1/12+1/20+1/30+1/42+1/56怎么做?我已经知道算式了,但我想求答案.1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8=（一个算式）=得数. 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=______1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90 ＝1/（1*2）+1/（2*3）+1/（3*4）+1/（4*5）+1/（5*6）+1/（6*7）+1/（7*8）+1/（8*9）+1/（9*10） ＝1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1 计算题2道1+2-3-4+5+6-7-8+.-1983-1984+1985+1986=又:1-1/2+1/6+1/12+1/20+1/30+1/40+1/72+1/56+1/90=急,急, 1/2+1/5+1/8+1/11+1/20+1/41+1/110+1/1640=1则1/2-1/5-1/8-1/11-1/20-1/41-1/110-1/1640=? 已知1/2+1/5+1/8+1/11+1/20+1/41+1/110+1/1640=1则1/2-1/5-1/8-1/11-1/20-1/41-1/110-1/1640=? 已知1/2+1/5+1/8+1/11+1/20+1/41+1/110+1/1640=1求:-1/2-1/5-1/8+1/11-1/20-1/41+1/110+1/1640的值. 已知1/2+1/5+1/8+1/11+1/20+1/41+1/110+1/1640=-1,计算-1/2-1/5-1/8-1/11-1/20-1/41+1/110+1/1640 已知1/2+1/5+1/8+1/11+1/20+1/41+1/110+1/1640=1,试计算-1/2-1/5-1/8+1/11-1/20-1/41+1/110+1/1640 (1+1/3+1/5+1/10+1/15+1/30)/(1/2+1/4+1/6+1/12+1/20+1/60)=​?简便计算方法 (1+1/3+1/5+1/10+1/15+1/30)/(1/2+1/4+1/6+1/12+1/20+1/60)=​?简算