I’ve been looking for quotes to put at the beginning of each chapter in my math games books. I found a delightful one by Mrs. LaTouche on the Mathematical Quotations Server, but when I looked up the original source, it was even better:
I am nearly driven wild with the Dorcas accounts, and by Mrs. Wakefield’s orders they are to be done now.
I do hate sums. There is no greater mistake than to call arithmetic an exact science. There are Permutations and Aberrations discernible to minds entirely noble like mine; subtle variations which ordinary accountants fail to discover; hidden laws of Number which it requires a mind like mine to perceive.
For instance, if you add a sum from the bottom up, and then again from the top down, the result is always different.
Again if you multiply a number by another number before you have had your tea, and then again after, the product will be different. It is also remarkable that the Post-tea product is more likely to agree with other people’s calculations than the Pre-tea result.
Try the experiment, and if you do not find it as I say, you are a mere sciolist*, a poor mechanical thinker, and not gifted as I am, with subtle perceptions.
Of course I find myself not appreciated as an accountant. Mrs. Wakefield made me give up the book to [my daughter] Rose and her governess (who are here), and was quite satisfied with the work of those inferior intellects.
— Maria Price La Touche
The Letters of A Noble Woman
London: George Allen & Sons, 1908
*sciolist: (archaic) A person who pretends to be knowledgeable and well informed. From late Latin sciolus (diminutive of Latin scius ‘knowing’, from scire ‘know’) + -ist.
Denise Gaskins' Let's Play Math 
Awesome quotation. I especially enjoyed the section about pre-tea / post-tea calculations. Insert “coffee” instead of “tea,” and I feel exactly the same way!
Yes, I agree! I’m sitting at Panera Bread mainlining caffeine for an all-day writing session right now.
All I remember is that I am always stuck when it comes the calculation of base, hypotenuses and perpendicular, which contain Sin, Cos and Tan values, then I learned a very simply method to remember it, take the initials and I made it like.
Some People have that means Sin=P/B
Curly Brown Hair that means Cos=B/H
Till Painted Black that means Tan=P/B
it looks crazy but I remember the values.