Notăm cu "M" mulțimea.
[tex]M=\left \{ x\:|\:x\:\in\:\mathbb{N} ,x-7<3\right \} [/tex]
[tex]x - 7 < 3[/tex]
[tex]x < 3 + 7[/tex]
[tex]x < 10[/tex]
[tex]x \: \in \: \mathbb{N} = > x \: \in \:\left \{ 0,1,2,3,4,5,6,7,8,9 \right \}[/tex]
[tex]=>M=\left \{ 0,1,2,3,4,5,6,7,8,9 \right \}[/tex]