JavaScript · Chapter 9 of 55
JavaScript Arithmetic
Arithmetic operators perform mathematical calculations on numbers: addition `+`, subtraction `-`, multiplication `*`, division `/`, modulus `%`, and exponentiation `**`.
JavaScript also supports increment `++` and decrement `--` operators to quickly add or subtract one from a variable.
Basic operations
The five basic arithmetic operators work as in standard math, and `%` returns the remainder of a division.
Increment and decrement
`x++` increases x by 1 (postfix, returns old value), `++x` does the same but returns the new value (prefix). `x--` and `--x` work similarly for decreasing.
Example 1 (javascript)
console.log(10 % 3);
console.log(2 ** 10);Output
1
1024Modulus gives the remainder; ** raises to a power.
Example 2 (javascript)
let count = 5;
count++;
console.log(count);Output
6Increment adds 1 to the variable.
Key points
- `%` returns the remainder of division.
- `**` raises a number to a power.
- `++` and `--` increment/decrement by one.
- Division `/` always returns a floating-point result if not evenly divisible.
💡 Note: Be careful with floating-point math — `0.1 + 0.2` does not exactly equal `0.3` due to binary representation.