The teacher handed out the math test papers.

1(1) 30 *1* 4+20 *1.2 * 5-(22.5 * 4+17 * 5) 65 (yuan)

(2)15.8-12 * (22.5/30) = 6.8 (yuan) 6.8/( 17/20)=8 (yuan)

2. The original price of these hats is 175*8= 1400 yuan.

If you want to go to Wu Shang Square, you need1400 * 0.8 =1120 (yuan).

If you go to Limin Shopping Mall, you need1400-1400/100 * 20 =1120 (RMB).

If you go to the middle department store: 175/ 12 = 14 ..., 7 (top), you need to buy a hat14 *10+7 =127 (.

Need127 * 8 =1016 (yuan)

Because it is1016 <1120, it is more cost-effective to buy it in Shangzhong department store.