What’s Arithmetic? Arithmetic deals with the study of numbers, especially with operations on those numbers, such as addition, subtraction, multiplication, and division. In mathematics, those operations are called arithmetic operations. Arithmetic operators are then the operators that are used in arithmetic operations. In PHP, we have a few arithmetic operators. They include: addition, subtraction, multiplication, division, modulus, and exponential operators. Let’s just run through the basic ones first. I mean, after all, it is just basic math. <?php $a = 2 + 2; // $a = 4 $b = 5 – 3; // $b = 2 $c = $a