For arbitrary precision mathematics PHP offers the Binary Calculator (BCMATH library of functions) which supports numbers of any size and precision, represented as strings.
The BCMATH library includes the following functions:
bcadd() - Add two arbitrary precision numbers
bccomp() - Compare two arbitrary precision numbers
bcdiv() - Divide two arbitrary precision numbers
bcmod() - Get modulus of an arbitrary precision number
bcmul() - Multiply two arbitrary precision number
bcpow() - Raise an arbitrary precision number to another
bcpowmod() - Raise an arbitrary precision number to another, reduced by a specified modulus
bcscale() - Set
default scale parameter for all bc math functions
bcsqrt() - Get the square root of an arbitrary precision number
bcsub() - Subtract one arbitrary precision number
This test uses 8 of the 10 (all but bcpowmod() and bcscale()) predefined functions included in the BCMATH library. This test is successful when a (correct)
result is displayed in the red box(es) for each of the functions.