My turn to state the obvious:
Add 200, subtract 20 (or vice versa).
Yep the technique I use. The question was
NOT how to calculate them it was how to:
practice reciprocal headings?
This is often used in aptitude selection as an accuracy and speed test. Clearly you have not sat aptitudes with this test.
Also, you have instruments (DI, VOR etc) with it on, in front of you: just read it off.
Also not a useful technique when you don't have one in aptitude testing.
Dunno what there is to practice really, you can either add/subract 180 in the head or not. If you can't, look at the DI and it'll visually tell you (my preferred methon ), or use a calculator......
Read the question again. Practice, I can do it fine. Wanted to use the software that was on pprune couple years back to practice this test.
Jonathan