2.2 *1/2+2÷1/30 = 90 minutes

3. 14÷2/3- 1/6=

4. 1200*( 1+0.2-0.4)= 1080

5.(6.5-6)÷6.5≈7%

6. 150/2÷(4+5+6)=5

4*5=20 5*5=25 6*5=30

7.3. 14*8*8=200.96

200.96*2=40 1.92≈40 1