Răspunsuri

2014-10-25T12:46:53+03:00
5(1+2+3+...+8)=5*(8*9:2)=5*(72:2)=5*36=180

1 5 1
2014-10-25T12:47:09+03:00
5+10+ ...+ 40= 5( 1+2+...+9)= 5 [( 9+10)/2]= 5 (90/2)= 5 X 45 = 225