Question

alege a ori b
hai dau​

Answer 1

$\it \rule{0.2}{0.2}_{a)\ \ 5\in\mathbb{N}\ \ (A)}\\ \\ \\ \rule{0.2}{0.2}_{b)\ \ \mathbb{Z}_ {+}=\mathbb{N}^*;\ \ \it2\in \mathbb{N}^* \Longrightarrow 2\in\mathbb{Z}_{+}\ \ \ (A)}}$

Answer 2

Răspuns:

N => multimea numerelor naturale : 0,1,2,3....

 Z+ => multimea numerelor intregi pozitive : +1,+2, +3, +4

ambele