Question

Determinati numerele naturale de forma 1x2y divizibile cu 5.

Answer 1

[tex]Pentru~a~fi~divizibil~cu~5,obligatoriu~ultima~cifra~va~fi\\ 0~sau~5.\\ 1x2y|5=\ \textgreater \ \left \{{{y=0,5} \atop {x=0,1,2,...,9}} \right. \\ Numerele~sunt:1020,1025,1120,1125,1220,1225,1320,1325,1420\\ 1425,1520,1525,1620,1625,1720,1725,1820,1825,1920,1925.[/tex]