[tex]\displaystyle \\
\texttt{Notatie: n = numarul de numere de 3 cifre crescatoare.} \\ \\
n = C_{10} ^3 - C_{10} ^2 = \frac{A_{10}^3}{P_3} -\frac{A_{10}^2}{P_2} = \frac{10\times 9 \times 8}{1\times 2\times 3} - \frac{10\times 9 }{1\times 2}= \\ \\
=10\times 3 \times 4 - 5\times 9 = 120 - 45 = \boxed{75 ~numere }[/tex]
