1/4+1/2-x=3/8
x=1/4+1/2-3/8
x=2/8+4/8-3/8
x=3/8
(7/8+1/2)-2/5
=(7/8+4/8)-2/5
=11/8-2/5
=55/40-16/40
=39/40
1-(1/6+4/9)
=1-(6/36+16/36)
=1-22/36
=1-11/18
=18/18-11/18
=7/18
水泥一共:1/2+3/8+5/6=12/24+9/24+20/24=41/20=2又1/20(吨)
1/4+1/2-x=3/8
x=1/4+1/2-3/8
x=2/8+4/8-3/8
x=3/8
(7/8+1/2)-2/5
=(7/8+4/8)-2/5
=11/8-2/5
=55/40-16/40
=39/40
1-(1/6+4/9)
=1-(6/36+16/36)
=1-22/36
=1-11/18
=18/18-11/18
=7/18
水泥一共:1/2+3/8+5/6=12/24+9/24+20/24=41/20=2又1/20(吨)