$ inquire a "Enter first number"
$ a = f$integer( a )
$ inquire b "Enter second number"
$ b = f$integer( b )
$ write sys$output "a + b = ", a + b
$ write sys$output "a - b = ", a - b
$ write sys$output "a * b = ", a * b
$ write sys$output "a / b = ", a / b  ! truncates down