6*(12分之5+15分之4-2分之1)
=6*5/12+6*4/15-6*1/2
=5/2+8/5-3
=25/10+16/10-30/10
=41/10-30/10
=11/10
(8分之1+4分之3)*(1-3分之1)
=(1/8+6/8)*2/3
=7/8*2/3
=7/12
743-92*51/23
=743-4*51
=743-204
=539
3/［(4分之3+(5分之4-5分之1))］
=3/(3/4+3/5)
=3/(15/20+12/20)
=3/(27/20)
=3*20/27
=20/9
5分之1/［(3分之1+5分之2)*11分之1］
=1/5÷(11/6*1/11)
=1/5÷1/6
=6/5