1/1*4+1/4*7+1/7*10+.+1/52*55*+1/55*58=?
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1/1*4+1/4*7+1/7*10+.+1/52*55*+1/55*58=?
1/1*4=(1/3)*(1-1/4)
1/4*7=(1/3)*(1/4-1/7)
1/7*10=(1/3)*(1/7-1/10)
1/1*4+1/4*7+1/7*10+.+1/52*55*+1/55*58
=(1/3)*(1-1/4)+(1/3)*(1/4-1/7)+(1/3)*(1/7-1/10)+……+(1/3)*(1/55-1/58)
=(1/3)*(1-1/4+1/4-1/7+1/7-1/10+1/10-……-1/55+1/55-1/58)
=(1/3)*(1-1/58)
=(1/3)*(57/58)
=19/58
1/4*7=(1/3)*(1/4-1/7)
1/7*10=(1/3)*(1/7-1/10)
1/1*4+1/4*7+1/7*10+.+1/52*55*+1/55*58
=(1/3)*(1-1/4)+(1/3)*(1/4-1/7)+(1/3)*(1/7-1/10)+……+(1/3)*(1/55-1/58)
=(1/3)*(1-1/4+1/4-1/7+1/7-1/10+1/10-……-1/55+1/55-1/58)
=(1/3)*(1-1/58)
=(1/3)*(57/58)
=19/58
1/1*4+1/4*7+1/7*10+.+1/52*55*+1/55*58=?
1/1×4+1/4×7+1/7×10+.+1/52×55+1/55×58
简便计算:1/55+2/55+3/55+4/55+5/55+6/55+7/55+8/55+9/55+10/55-11/1
(10-4/55*1)+(9-4/55*2)+(8-4/55*3)+...+(2-4/55*9)+(1-4/55*10)
简便计算,(10-7/55*1)+(9-7/55*2)+(8-7/55*3)+...+(1-7/55*10)
1 2 5 10 13 26 29 58 【】 2 3 5 8 13 21【】 55 2 1 4 4 6 7 8 10【
(1+2+3+4+5+6+7+8+9+10)÷55=?
vb 显示1+2+3+4+5+6+7+8+9+10=55
(10-7/55×1)+(9-7/55×1)+(8-7/55×1)+.+(1-7/55×1)怎么简算?
10:22,5:30,9:55,10:50,1:30;2:40,3:10,4:58,6:18,7:48,8:15,9:4
1+2/3*4+55+6-7/8=1添括号急!
4+7+10+.+55+58=?速算