The Number of Love by Roseanna White

Margot De Wilde is a mathematical genius and the only woman code breaker in England's "room 40."  The other code breakers treat her as an equal and sometimes forget she is a mere girl of 17, and that is how she likes it.  Numbers speak to her, and she feels totally comfortable in the world of computation, but not so much in the level of society to which she was born.  When the Lord prompts her to become friends with the new girl in the secretary pool, Dot, she meets Dot's Navy officer brother, Drake.  Like Margot, Drake is more than he seems, and fate keeps bringing them together. 

This is actually the first in the series, the second of which is On Wings of Devotion, which I already read.  Despite this one's SUPER cheesy title, I enjoyed it quite a bit.  It takes place during the same time period as the second one, but just follows a different couple's relationship.  I thought it was cleaver that White included some of the same scenes as the second novel but told from a different character's point of view.  I also liked the way White portrayed how the numbers acted in Margot's mind.  I have been married to a mathematician for 30 years, and I don't think he sees numbers quite like that, but I could imagine a mathematical genius seeing the world that way.  I know in my father's last hours he was reduced to just using numbers to communicate. It was intriguing. I look forward to the third book, which, according to the descriptive blib, follows a different couple mentioned in the second book. (2019, 370)