SSUB
Synopsis
SSUB(numstr1,numstr2)
Arguments
numstr1  The minuend. An expression that resolves to a number or numeric string. 
numstr2  The subtrahend. An expression that resolves to a number or numeric string. 
Description
The SSUB function subtracts numstr2 from numstr1, expressed as either numbers or as strings, and returns the result. Leading plus signs and leading and trailing zeros are ignored. A string is parsed as a number until a nonnumeric character is encountered. Thus “7dwarves” is parsed as 7. Nonnumeric strings and null strings are parsed as 0.
Arithmetic Operations

To perform arithmetic operations on numeric strings, use the SADD, SSUB, SMUL, and SDIV functions.

To perform arithmetic operations on floating point numbers, use the FADD, FSUB, FMUL, and FDIV functions, or use the standard arithmetic operators.

To perform integer division, use the DIV function. To perform modulo division, use the MOD function.

To perform arithmetic operations on corresponding elements of dynamic arrays, use the ADDS, SUBS, MULS, DIVS, and MODS functions.

To perform numeric comparison operations, use the SCMP function, or use the standard comparison operators.
Examples
The following examples use the SSUB function to subtract two numeric strings. All of these examples return 4:
PRINT SSUB(7,3)
PRINT SSUB("7","3")
PRINT SSUB("+7.00","003")
PRINT SSUB("7dwarves","3wishes")
All of the following examples return 7:
PRINT SSUB(7,0)
PRINT SSUB("7","")
PRINT SSUB("7","three")