Выполни вычисления по образцу 470 + 80 = 470 + (30 + 50) = (470 + 30) + 50 = 500 + 50 = 550 560 – 90 = 560 – (60 + 30) = (560 – 60) – 30 = 500 – 30 = 470 360 + 50 = 360 + ( + ) = (360 + ) + = + = 290 + 70 = 290 + ( + ) = (290 + ) + = + = 830 – 80 = 830 – ( + ) = (830 – ) – = – = 420 – 60 = 420 – ( + ) = (420 – ) – = – = к списку
290+70=290+(30+40)=(290+30)+40=320+40=360
830 -80=830-(40+40)=(830-40)-40=790-40=750
420-60=420-(30+30)=(420-30)-30=390-30=360.
360+50=360+(40+10)=(360+40)+10=400+10=410
290+70=290+(10+60)=(290+10)+60=300+60=360
830-80=830-(30+50)=(830-30)-50=800-50=750
420-60=420-(20+40)=(420-20)-40=400-40=360