(359-59):50=300:50=6
450:9+720:90=50+8=58
800:(957-917)=800:40=20
(456+440:10)×2=(456+44)×2=500×2=1000
900:30+5×(680-640)=30+5×40=30+200=230
630:9+(450+90)=70+540=610
30×5+(456-400)=150+56=206
1000:(67+33)×5=1000:100×5=10×5=50
5×(567-507):100=5×60:100=300:100=3
360:6-(590-530)=60-60=0