In section 1.4, we are introduced to the concepts of modular congruence, congruence classes, and their basic arithmetic. Here are three simple problems to give you a taste and some extra practice.
1. Find three different ways to symbolically represent the set of all integers $a$ such that is divisible by .

2. List 5 elements in the following congruence class, including atleast 2 positive and 2 negative:

3. Calculate the following, and reduce the solution to standard form.

4. For the following equation, find the congruence class (in standard form) that solves the equation.