11除与三分之四+5乘四分之三
=11÷(4/3)+5×(3/4)
=33/4+15/4
=48/4
=12;
3乘（十八分之五+12分之1）减六分之五
=3×（5/18+1/12）-5/6
=5/6+1/4-5/6
=1/4;
如果本题有什么不明白可以追问,