Log book

How many of the youngsters of today even know what this is?  Never mind how to use it.

Our neighbour has asked W to help her daughter with some maths.  In a former life, W was a maths teacher - but acknowledges that he is "a bit out of date".  He used a book like this to calculate sins, cosins, tans, etc.  Nowadays, you just need a decent calculator.

Our discussion led to me retrieving this from my shelf.  I don't think this is the log book I had as a schoolkid, as it is marked 19p in the front, and my use of log books at school would have pre-dated decimalisation.  

I think I bought this (possibly in a second hand shop) for the tables of square numbers and square roots, because at one time I did a lot of mathematical puzzles.  But it brings back memories!