Răspuns:
18.
M13={13, 26, 39, 52, 65, 78, 91}
19.
D28={1, 2, 4, 7, 14, 28} Suma este 56.
20.
54=2 • 3^3
75=3 • 5^2
120=2^3 • 3 • 5
300=2^2 • 3 • 5^2
M₁₃={13, 26, 39, 52, 65, 78, 91}
____________
D₂₈={1, 2, 4, 7, 14, 28}
1+2+4+7+14+28=56
___________
54=2·3³
75=3·5²
120=2³·3·5
300=2²·3·5²
