Riddle: I have some matchsticks set up like this: I + XI = X. If you do not know Roman numerals, here is a quick starter: I=1 II=2 III=3 IV=4 V=5 VI=6 VII=7 VIII=8 IX=9 X=10 XI=11 XII=12 XIII=13 XIV=14 XV=15...... Of course, I + XI = X is wrong. You are told to move the minimum number of matchsticks to make the question correct. So, how many do you have to move?
Answer: Most people would get to one move at the least, but the real answer is zero moves. If you rotate the whole question around 180 degrees, it will display this: X = IX + I