Răspuns:
a=1+2+3+.................+9
a= (1+9)+............(4+6)+5
a=10x4+5
a=45
b=11+22+33+.................+99
b= (11+99)+............(44+66)+55
b=110x4+55
b=440+55
b=495
c=111+222+333+.................+999
c= (111+999)+............(444+666)+555
c=1110x4+555
c=4440+555
c=4995
Explicație pas cu pas:
