1) 3/4+9 3/4(九又四分之三)+99 3/4（九十九又四分之三）+999 3/4（九百九十九又四分之三）+1
=1) 3/4+9 3/4(九又四分之三)+99 3/4（九十九又四分之三）+999 3/4（九百九十九又四分之三）+1/4+1/4+1/4+1/4
=1+10+100+1000
=1111
（2）1-1/2-1/4-1/8-1/16-1/32-1/64
=1-(1/2+1/4+1/8+1/16+1/32+1/64)-1/64+1/64
=1-(1/2+1/4+1/8+1/16+1/32+1/64+1/64)+1/64
=1-1+1/64
=1/64
(3) 1/3x7+1/7x11+1/11x15+……+1/55x59
=1/4*(1/3-1/7)+1/4*(1/7-1/11)+.1/4*(1/55_1/59)
=1/4*(1/3-1/7+1/7_1/11+.+1/55-1/59)
=1/4*(1/3-1/59)
=14/177
(4) 1/6+1/12+1/20+1/30+1/40 (最后应该是1/42）
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1/2-1/7
=5/14
(5) 7+77+777+7777+77777
=7*（1+11+111+1111+11111）
=7*12345
=86415
6) 8×（3.1-2.85）×12.5×（1.62+2.38）
=8×12.5X（3.1-2.85）×（1.62+2.38）
=100*0.25*4
=100*1
=100
（7）100+99-98+97-96+……+3-2+1
=100+（99-98）+（97-96）.+（3-2）+1
=100+49+1
=150