(359-59):50=300:50=6
450:9+720:90=30+8=38
800:(957-917)=800:40=20
(456+440:10)•2=(456+44)•2=500•2=1000
900:30+5•(680-640)=930:30+5•40=31+200=231
630:9+(450+90)=630:9+540=70+540=610
30•5+(456-400)=30•5+56=150+56=206
1000:(67+33)•5=1000:100=10
5•(567-507):100=5•60:100=300:100=3
360:6-(590-530)=360:6-60=60-60=0