API Platform Conference 2025

BcMath\Number::mul

(PHP 8 >= 8.4.0)

BcMath\Number::mulMultiplies an arbitrary precision number

Description

public BcMath\Number::mul(BcMath\Number|string|int $num, ?int $scale = null): BcMath\Number

Multiplies $this by num.

Parameters

num
The multiplier.
scale
scale explicitly specified for calculation results. If null, the scale of the calculation result will be set automatically.

Return Values

Returns the result of multiplication as a new BcMath\Number object.

When the BcMath\Number::scale of the result object is automatically set, the sum of the BcMath\Number::scales of the two values used for multiplication is used.

That is, if the BcMath\Number::scales of two values are 2 and 5 respectively, the BcMath\Number::scale of the result will be 7.

Errors/Exceptions

This method throws a ValueError in the following cases:

  • num is string and not a well-formed BCMath numeric string
  • scale is outside the valid range
  • BcMath\Number::scale of the result object is outside the valid range

Examples

Example #1 BcMath\Number::mul() example when scale is not specified

<?php
$number
= new BcMath\Number('1.234');

$ret1 = $number->mul(new BcMath\Number('2.3456'));
$ret2 = $number->mul('-3.4');
$ret3 = $number->mul(7);

var_dump($number, $ret1, $ret2, $ret3);
?>

The above example will output:

object(BcMath\Number)#1 (2) {
  ["value"]=>
  string(5) "1.234"
  ["scale"]=>
  int(3)
}
object(BcMath\Number)#3 (2) {
  ["value"]=>
  string(9) "2.8944704"
  ["scale"]=>
  int(7)
}
object(BcMath\Number)#2 (2) {
  ["value"]=>
  string(7) "-4.1956"
  ["scale"]=>
  int(4)
}
object(BcMath\Number)#4 (2) {
  ["value"]=>
  string(5) "8.638"
  ["scale"]=>
  int(3)
}

Example #2 BcMath\Number::mul() example of explicitly specifying scale

<?php
$number
= new BcMath\Number('1.234');

$ret1 = $number->mul(new BcMath\Number('2.3456'), 1);
$ret2 = $number->mul('-3.4', 10);
$ret3 = $number->mul(7, 0);

var_dump($number, $ret1, $ret2, $ret3);
?>

The above example will output:

object(BcMath\Number)#1 (2) {
  ["value"]=>
  string(5) "1.234"
  ["scale"]=>
  int(3)
}
object(BcMath\Number)#3 (2) {
  ["value"]=>
  string(3) "2.8"
  ["scale"]=>
  int(1)
}
object(BcMath\Number)#2 (2) {
  ["value"]=>
  string(13) "-4.1956000000"
  ["scale"]=>
  int(10)
}
object(BcMath\Number)#4 (2) {
  ["value"]=>
  string(1) "8"
  ["scale"]=>
  int(0)
}

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