456+125+67+90+67+45+23+45

1)456+125=5812)581+67=6483)648+90=7384)738+67=8055)805+45=8506)850+23=8737)873+45=918

456+125+ (67+23) +67+ (90+45+45) = (581+67) +90+ (90+90) = 648+3*90=

=648+270=918

или (456+67+67)+125+23+(90+45+45)=(456+134)+125+23+(90+90)=

=590+125+23+180=(590+180)+(125+23)=770+148=918