\[\begin{aligned} \mathbb{N} &=\{1,2,3,\cdots\} \quad \text{(the set of }\textbf{natural numbers}\text{ or positive integers)} \\ \mathbb{Z} &=\{\cdots,-3,-2,-1,0,1,2,3,\cdots\} \quad\text{(the set of...\[\begin{aligned} \mathbb{N} &=\{1,2,3,\cdots\} \quad \text{(the set of }\textbf{natural numbers}\text{ or positive integers)} \\ \mathbb{Z} &=\{\cdots,-3,-2,-1,0,1,2,3,\cdots\} \quad\text{(the set of }\textbf{integers}) \\ \mathbb{Q} &=\left\{ \frac{n}{m} \mid n,m\in\mathbb{Z}\text{ and }m\neq 0\right\} \quad \text{(the set of }\textbf{rational numbers}) \\ \mathbb{R} &=\text{the set of }\textbf{real numbers}\\ \mathbb{C} &= \left\{a+bi \mid a,b \in \mathbb{R} \right\} \quad \text{(the set of …
If a divides b, we write a∣b, and we may say that a is a divisor of b, or that b is a multiple of a, or that b is a divisible of a. For example, a∣a b...If a divides b, we write a∣b, and we may say that a is a divisor of b, or that b is a multiple of a, or that b is a divisible of a. For example, a∣a because we can write a⋅1=a; 1∣a because we can write 1⋅a=a; a∣0 because we can write a⋅0=0.