14分之9减7分之4乘8分之5
=9/14-5/14
=4/14
=2/7
100乘（10分之1-100分之1）
=100x1/10-100x1/100
=10-1
=9
43乘42分之19
=(42+1)x19/42
=42x19/42+19/42
=19又19/42
12分之5乘11-12分之5
=5/12x(11-1)
=5/12x10
=25/6