JavaScript Built-in Constants Operations that return NaN
Example
Mathematical operations on values other than numbers return NaN.
"a" + 1
"b" * 3
"cde" - "e"
[1, 2, 3] * 2
An exception: Single-number arrays.
[2] * [3] // Returns 6
Also, remember that the + operator concatenates strings.
"a" + "b" // Returns "ab"
Dividing zero by zero returns NaN.
0 / 0 // NaN
Note: In mathematics generally (unlike in JavaScript programming), dividing by zero is not possible.
