几题数学六年级计算题1又1/2-1/4-1/8-1/16-1/32-1/64-1/1281/2005+2/2005+3/
3个回答

第一题,解

3/2-1/4-1/8-1/16-1/32-1/64-1/126

= 3/2-(1/4+1/81/16+1/32+1/64+1/126)

=3/2- [(32+16+8+4+2+1)/128]

=3/2-63/128

=192/128-63/128

=129/128

=1又1/128

第二题,解

1/2005+2/2005+3/2005+.+2004/2005

=[【(1+2004)×2004】÷2] / 2005

=[(2005×2004)÷2] / 2005

=2005×2004×2004× 1/2 × 1/2005

=1002

第三题,解

401040104010/200520052005

=401040104010÷200520052005

=2