I recently whined a lot about the Egyptian multiplication puzzle which not only has no real statement, but has a very strange example that we are supposed to follow.

If the idea is "simple" to understand, the statement asks the reader to follow the example to code the algorithm. But what happens in the example and the comments don't really match my definition of an algorithm :

12 * 5

= 12 * 4 + 12 # Divide 5 by 2, the remain is 1 and 5=2×2+1, thus 12*5=12*(2*2+1)=12*2*2+12=24*2+12

= 24 * 2 + 12 # Divide 2 by 2, 2=1*2+0 and 12*5=24*(1*2+0)+12=48*1+12

= 48 * 1 + 12 # Divide 1 by 2, 1=0*2+1 and 12*5=48*(0*2+1)+12=12+48

= 48 * 0 + 12 + 48 # End of the algorithm

= 60

Look at for instance, line 4 of the example. You start with 48*1 + 12. The comment explains to you how to get from here, to the next line 48*0 + 12 + 48. OK.

Now look at line 2. You start with 12*4 + 12. The comment explains how to get, not from that line, but from the PREVIOUS line, to the next line.

I thought that was ill presented and misleading, and would really benefit from rephrasing. It would be even better if the description of the algorithm would not follow an example.