540/60=9,540*2/(6+9)=72

2)(98+ 120+ 166/)4=96

3)95*3-93*2=99

4)94*5-96*4=86

5)30*4/(6-4)=60,60*6=360,

360*2/(6+4)=72

6)(240+40)/2= 140

240- 140 = 100,100/2 = 50,50/10 = 5 times.

7)A =(2 1 * 2+ 16 * 2-22 * 2)/2 = 15。

B = 2 1+22- 16 = 27

c = 22+ 16-2 1 = 17