Books
I Want to Be a Mathematician
Paul Halmos
A good stock of examples as large as possible is indispensable for a thorough understanding of any concept.
The Man Who Loved Only Numbers
Paul Hoffman
A mathematician is a machine for turning coffee into theorems.
Letters to a Young Mathematician
Ian Stewart
Mathematics is a product of human minds but not bendable to human will.
The Art of Mathematics
Jerry P. King
YouTube Channels
Podcasts
In Is There Mathematics Beyond the Equal Sign?, the speaker emphasizes that mathematics is not a linear ladder but a network of ideas that can be approached from many directions.