260-40,450+30,640+200,450+300,320+50,530-20,770-330,340-100 Образец 260-40=200+(60-40)=200+20=220

380,840,750,370,550,740,360

450+30=400+(50+30)=400+80=480640+200=40+(600+200)=40+ 800=840450+300=50+(400+300)=50+ 700=750320+50=300+(20+50)=300+70=370530-20=500+(30-20)=500+10=510770-330=(700-300)+(70-30)=400+40=440340-100=40+(300-100)=40+ 200=240