Number Theory/Notation and Introduction to proof

Notation

$\mathbb{N}$ is the set of positive integers, also called the natural numbers.

$\mathbb{Z}$ is the set of all integers.

$\mathbb{Q}$ is the set of all rational numbers.

$𝔸$ is the set of algebraic numbers.

$ℝ$ is the set of real numbers.

$ℂ$ is the set of complex numbers.