(2*3*4*5)*(1/2-1/3-1/4-1/5)
2\1+(3\1+3\2)+(4\1+4\2+4\3)+(5\1+5\2+5\3+5\4)+.+(40\1+40\2+.
计算 1/2-(1/3+2/3)+(1/4+2/4+3/4)-(1/5+2/5+3/5+4/5)+...-(1/21+2
一道奥数题,急救!(1+1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/
(1) 1,1/3,1/5,1/7,1/9 (2)- 1/2*1,1/2*2,- 1/2*3,1/2*4,-1/2*5
1/1 ,1/2 ,2/2,1/3,2/3,3/3 ,1/4,2/4,3/4,4/4 ,1/5,2/5----(找规律)
5/9+(3/4-1/2)
计算1/2+(1/3+2/3)+(1/4+2/4+3/4)+(1/5+2/5+3/5+4/5)+.+(1/50+2/50
(1/3+2/3)+(1/4+2/4+3/4)+(1/5+2/5+3/5+4/5)+.+(1/100+.99/100)=
如何计算:(1-1/2*2)(1-1/3*3)(1-1/4*4)(1-1/5*5)、、、(1-1/2000*2000)拜
判断:1/4+2/5+3/5=1/4+(2/5+3/5)对错
1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6 (简便方法)
1/2+(-2/3)-(-4/5)+(-1/2)-(+1/3)