=40+1+50+1+60+1
=153
51又四分之一乘五分之四加六十一又五分之一乘六分之五加71又六分之一...
51又四分之一乘五分之四加六十一又五分之一乘六分之五加71又六分之一乘七分之六 =(50+5\/4)x4\/5+(60+6\/5)x5\/6+(70+7\/6)x6\/7 =50x4\/5+5\/4x4\/5+60x5\/6+6\/5x5\/6+70x6\/7+7\/6x6\/7 =50+1+60+1+70+1 =183
51又四分之一乘以五分之四加61又五分之一乘以六分之五加七十一又六分...
51又1\/4×4\/5+61又1\/5×5\/6+71又1\/6×6\/7 =（50+5\/4）×4\/5+（60+6\/5）×5\/6+（70+7\/6×6\/7）=50×4\/5+5\/4×4\/5+60×5\/6+6\/5×5\/6+70×6\/7+7\/6×6\/7 =40+1+50+1+60+1 =153
1\/5×1\/6+1\/6×1\/7+1\/7×1\/8+1\/8×1\/9+1\/9×1\/10这道题用简便方法怎样做...
1\/5×1\/6=1\/5-1\/6,1\/6×1\/7=1\/6-1\/7,1\/7×1\/8=1\/7-1\/8,1\/8×1\/9=1\/8-1\/9 1\/9×1\/10=1\/9-1\/10 1\/5×1\/6＋1\/6×1\/7＋1\/7×1\/8＋1\/8×1\/9＋1\/9×1\/10 =1\/5-1\/6+1\/6-1\/7+1\/7-1\/8+1\/8-1\/9+1\/9-1\/10 =1\/5-1\/10 =2\/10-1\/10 =...
简便计算13又5分之一乘6分之5加16又4分之一乘5分之4减17又3分之一乘...
71又6分之1乘7分之6+61又5分之1乘6分之5+51又4分之1乘5分之4+41又3分之1乘4分之3 =(71×6+1)×1\/7+(61×5+1)×1\/6+(51×4+1)×1\/5+(41×3+1)×1\/4 =427×1\/7+306×1\/6+205×1\/5+124×1\/4 =61+51+41+31 =184 ...
41又1\/3×3\/4+51又1\/4×4\/5+61又1\/5×5\/6+71又1\/6×6\/7 的梯等式简便...
=124\/3×3\/4+205\/4×4\/5+306\/5×5\/6+427\/6×6\/7 =31+41+51+61-发发汗 =？
1\/4*5*6 +1\/5*6*7 +1\/6*7*8+...+1\/98*99*100如何计算?
解析:=247\/9900.关键是要把1\/4*5*6这种等式拆成差式。我们知道，1\/n(n+1)=1\/n-1\/(n+1)，于是 1\/n(n+1)(n+2)=[1\/n-1\/(n+1)]*1\/(n+2)=1\/n(n+2)-1\/(n+1)*1\/(n+2)=1\/2*(1\/n-1\/(n+2))-[1\/(n+1)-1\/(n+2)]这样加起来，可以消去许多中间项，最后...
3×4分之1+4×5分之1+5×6分之1+6×7分之1+7×8分之1=?
1\/n*(n+1)=1\/n-1\/(n+1)3×4分之1+4×5分之1+5×6分之1+6×7分之1+7×8分之1 =1\/3-1\/4+1\/4-1\/5.+1\/7-1\/8 =1\/3-1\/8 =5\/24
3×4分之1+4×5分之1+5×6分之1+6×7分之1+7×8分之1+8×9分之1...
=3分之1-4分之1+4分之1-5分之1+5分之1-6分之1+6分之1-7分之1+7分之1-8分之1+8分之1-9分之1 =3分之1-9分之1 =9分之2
1\/4*5*6+1\/5*6*7+1\/6*7*8+1\/7*8*9+...1\/98*99*100
解：1\/(4×5×6)=1\/2[1\/(4×5)-1\/(5×6)]1\/(5×6×7)=1\/2[1\/(5×6)- 1\/(6×7 )]1\/(6×7×8)=1\/2[1\/(6×7)- 1\/(7×8)]………1\/(98×99×100)=1\/2[1\/(98×99)-1\/(99×100)]∴1\/(4×5×6)+ 1\/(5×6×7)+ 1\/(6×7×8)+…..+ 1\/(98...
5又6分之1=4又几分之几等于3又几分之几等于2又几分之几等于1又几分之...
5又6分之1=4又6分之7=3又6分之13=2又6分之19=1又6分之25
