If I tell you the answer you'll soon forget it again. If you find it for yourself you'll remember it better. All you'll ever need to know is to be found
here.
The conversion formula you need is found under bullet point thirteen in the contents list - Mach numbers, true vs calibrated airspeeds etc.
IAT = OAT = ...... etc.
Good luck with developing your navigation skills - you can't overdo it. Today you have no "old school wheel." Tomorrow it may be the SatNav that lets you down...
