n=5k+1
n+4=5k+1+4=5k+5=5p
n=10r+6
n+4=10r=6+4=10r+10=10q
n+4=[5;10]t=10t
n=10t-4
100<10t-4<500 |+4
104<10t<504 |:10
10,4<t<50,4 si t∈N
t∈{11;12....50}
10t-4∈{106;116;126......;486;496} care toate verifica cerintele
in total 50-11+1=50-10=40de numere
cam ciudata problema,de obicei solutia este unica, probabil ai gresit niste date