I'm starting to learn CS all over again at the old age of 40, and had the pleasure to rediscover mathematics thanks to: - Discrete Mathematics with Applications, by Susanna Epp, or - Discrete Mathematics and Its Applications, by Kenneth Rosen (both have the same content, choose the style that you prefer), and - Concrete Mathematics, by our lord and savior Donald Knuth. I don't plan on reading TAOCP anymore as I would be dead by the time I finish reading everything else, but those introductory books are very good for beginners.
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