hellp!!! my!!!! pomocy!!! plis jak sprytnie obliczyć sumy???!!! 173+68=??? 549+262=??? 398+298=??? 47•12=??? 125•8=??? 38•25=??? 58•11=??? pomocyyyyyyyyy!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

173+68 = (170+3)+(70-2)=170+3+70-2=240+1=241 549+262=(550-1)+(260+2)=550-1+260+2=810+1=811 398+298=(400-2)+(300-2)=400-2+300-2=700-4=696 47*12=(50-3)*12=600-36=564 125*8=(100+25)*8=800+25*8=800+25*2*4=800+100*2=800+200=1000 38*25=(40-2)*25=10*4*25-2*25=10*100*50=1000-50=950 58*11=58*(10+1)=58*10+58*1=580+58=638

173+68= 173+7+61=180+61=241 549+ 262= 549+ 51+ 211= 600+211=811 398+298= 398+2+296=400+296=696 47* 12= 47*10+47*2= 470+ 50*2-3*2= 470+100-6= 570-6=564 125*8=100*8+25*8=800+200=1000  38*25= 30*25+ 8*25= 750 +200=950 58*11= 58*10+58*1= 580+58= 638