The SSUB function performs string subtraction of two base 10 string numbers.
expr1 and expr2 are strings consisting of numeric characters, optionally including a decimal part.
The SSUB function can be used with numbers that may exceed a valid range with standard arithmetic operators.
The PRECISION declaration has no effect on the value returned by SSUB.
A = 2.3000000123456789
Displays -2.6999999876543212 to the screen.