Here's the problem:

I want to input any given course within the 360° of a circle and output the possible courses to steer if I came left or right 15°, 30°, 45°, 60°, 75°, or 90°.

So, if I were to use a course of 000° as my base input, it would look something like this:

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BASE COURSE: 000°

LEFT diff RIGHT

345° 15 015°

330° 30 030°

315° 45 045°

300° 60 060°

285° 75 075°

270° 90 090°

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If I were to change the base course input, all numbers would instantly update:

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BASE COURSE: 120°

LEFT diff RIGHT

105° 15 135°

090° 30 150°

075° 45 165°

060° 60 180°

045° 75 195°

030° 90 210°

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One big thing that I need with this is to be able to subtract numbers to the left while treating 000° the same as 360° so that if I subtract (come left) 45° from the course 030° I get 345° and not -15.

Is this even possible in Excel without any VB programming? Am I using the wrong functions?

Thank you, in advance, for any help you might give on this.

Mike