The Housekeeper and the Professor by Yoko Ogawa

A book club book, I enjoyed it more than the review suggests. Unusually, it was exactly the right length for what it had to say. 
I have to take it on faith that a deep understanding of math is somehow transcendent; I’ve tried, but apart from a passing fascination with the Golden Ratio, I hit a wall at school which I have never been able to scale.