def add$($a$,$ b$)$: return a $+$ b def subtract$($a$,$ b$)$: return a $-$ b def multiply$($a$,$ b$)$: return a $*$ b def divide$($a$,$ b$)$: if b $==0$: return "Cannot divide by zero." else: return a $/$ b # Testing the functions with sample inputs print$($add$(5,3))$ # $8$ print$($subtract$(10,4))$ # $6$ print$($multiply$(7,2))$ # $14$ print$($divide$(12,4))$ # $3\mathrm{.}0$ print$($divide$(8,0))$ # "Cannot divide by zero."