2, 90- 12×5=30

3. 1687÷7+29=270 cases

4.400× 7+660 = 3460m

5,80 ÷ 2× 3 =120m

6. 10×7-2=68 years old

7.400×4- 120 = 1480m 1480-400 = 1080m。

8. 130+85- 158=57 copies

9. 1200-236-402=562 sets.

10,8× 2+8 = 24 people

1 1, 100+40+ 100=240 yuan.

12,42× 3-42 = 84 people,

13,200-40+200 = 360 yuan 360 < 390, so I can't buy it.

14,210+25+210 = 435 Completed task 435+20-400=55.

15, 18÷6×8=24 yuan

16,2× 4× 23 =184 yuan.

17,24× 7 ÷ 6 = 28 bottles

18,40 ÷ 2 ÷ 4 = 5 boxes

19, (158+ 16)×3=522 yuan.

20, (1 1-3)×7=56 km.

2 1, 27×3×4=324 flowers

22,62 ÷ 2× 3 = 93 yuan

23, (48- 12)× 10=360 yuan.

24, (420+50)×6=2820 yuan

25,42 ÷ 2× 7 =147 yuan

26, 134×2×5= 1340.