An intriguing little life hack for calculating percentages:
X% of Y = Y% of X
So, for example, if you need to calculate 4% of 75 mentally, just swap the numbers and calculate 75% of 4, which is much easier.
Understandably, this is somewhat obvious from a mathematical point of view (100 in the denominator moves to the second factor), but nobody has been doing this in mental calculations, right?
Hi, I'm Rauf Aliev. 