(PHP 4, PHP 5, PHP 7, PHP 8)
bcsub — Subtract one arbitrary precision number from another
num1The left operand, as a string.
num2The right operand, as a string.
scalenull, it will default to the default scale set with bcscale(),
       or fallback to the value of the
       bcmath.scale INI directive.
      
     The result of the subtraction, as a string.
This function throws a ValueError in the following cases:
num1 or num2
     is not a well-formed BCMath numeric string.
    scale is outside the valid range.
    | Version | Description | 
|---|---|
| 8.0.0 | 
       scale is now nullable.
       | 
     
Example #1 bcsub() example
<?php
$a = '1.234';
$b = '5';
echo bcsub($a, $b);     // -3
echo bcsub($a, $b, 4);  // -3.7660
?>