The value of x - n * y, where n is the quotient rounded toward zero of the division x / y
| InvalidOperationException | x or y is signaling NaN, x = ±∞, y = ±0.0 | 
| UnderflowException | result is too small to be represented | 
| DivisionByZeroException | y = 0.0 | 
| InexactException | the result is inexact | 
| x | y | fmod(x, y) | 
|---|---|---|
| NaN | any | NaN | 
| any | NaN | NaN | 
| ±∞ | any | NaN | 
| any | 0.0 | NaN | 
| any | ±∞ | NaN | 
decimal32 x = "18.5"; decimal32 y = "4.2"; assert (fmod(x, y) == decimal32("1.7"));
Calculates the remainder of the division x / y