1.a) n=1•2•3•4•5+1•2•3•4•5•6+.....+1•2•3•....•194 n=3•5•(1•2•4+1•2•4•6+.....+1•2•4•6•7•8....•194 ) n=15•(1•2•4+1•2•4•6+.....+1•2•4•6•7•8....•194 ) se impare exact la 15
b)n=1•2•3•4•5+1•2•3•4•5•6+.....+1•2•3•....•194 n=4•5•(1•2•3+1•2•3•6+.....+1•2•3•6•7•8....•194 ) n=20•(1•2•3+1•2•3•6+.....+1•2•3•6•7•8....•194 ) se imparte exact la 20
c) n=1•2•3•4•5+1•2•3•4•5•6+.....+1•2•3•....•194 n=3•4•5•(1•2•4+1•2•4•6+.....+1•2•4•6•7•8....•194 ) n=60•(1•2+1•2•6+.....+1•2•6•7•8....•194 ) se imparte exact la 60
2. daca x/y=4/11 si cel mai mare divizor comun este 36 x=4*36=144 y=11*36=396