Please suggest a book on mathematics that helps with learning concepts in a fun way that one couldn’t grasp in studying years. Just to give you some context, a friend of mine keeps doing some number sequences and this even helps him not get bored during free time. Some say he even discovers something new incidentally and has whole lot fun mathematically finding new things though his work doesn’t relate to mathematics in any way. This is because he learnt practical mathematics in fun way during school days. Is there a way I can too have such fun in mathematics to play with mathematics mentally in free time ? Can you please suggest some such book ?
by Excellent_Aside_2422