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

15*10+(30-20)•5= 150+10•5=200 15•10+30-20•5= 150+30-100= 80 120-+320:4)•2=(120+80)•2=400. 120+320):(4•2)=440:8=55