Result is Number1 << Number2
    which should be preferred for portability.
The shift behaves as if operating on an unlimited length two's complement representation. Shifting by a negative amount is the same as shifting by the same positive amount in the other direction.
In coroutining mode, if Number1 or Number2 are uninstantiated, the call to <</3 is delayed until these variables are instantiated.
Success:
    Result is 1 << 3.		% gives Result = 8
    Result is 5 << 1.		% gives Result = 10
    Result is 10 << -1.		% gives Result = 5
    Result is -5 << 1.		% gives Result = -10
Error:
    Result is 1.1 << 3.		% type error