Răspuns:
Explicație pas cu pas:
card A = 20 si card B = 5
card AxB = card BxA = card A x card B = 20x5 = 100
card AxA = card A x card A = 20 x 20 = 400
card BxB = card B x card B = 5 x 5 = 25.
[tex]\it card(A\times B)=card(A)\cdot card (B)\\ \\ card(A\times A)=card(A)\cdot card (A)[/tex]
