15•10+(30–20)•5=? 15•10+30–20•5=? (120+320:4)•2=? (120+320):(4•2)=?

Question

15•10+(30–20)•5=?
15•10+30–20•5=?
(120+320:4)•2=?
(120+320):(4•2)=?

Answer 1

1) 150 + 50 = 200
2) 150 + 30 - 100 = 180 - 100 = 80
3) (120 + 80) × 2 = 200 ×2 = 400
4) 440 : 8 = 55