These are examples of the math operators in PHP that help perform basic arithmetic and manipulate numeric values within the code. When looking at the addition, subtraction, multiplication, and division sections the answers are relatively self explanatory. You are just adding, subtracting, multiplying, or dividing the two variables. When looking at the Modulus section, you are just taking the remainder of x divided by y. For pre-increment and decrement, this changes the first value, and then returns it. For post increment and decrement, this returns the first value, then changes it.