PDF file. Welcome to Algebra: Numbers 01. This 38-page teach-yourself unit is a very slow introduction to natural numbers and whole numbers presented in small bite-sized chunks. Nibble, nibble, gnosh, gnosh, learn a little algebra. It is slow and easy. Topics include natural numbers, whole numbers, odd numbers, even numbers, square numbers, triangular numbers, and a math recreation called mathemagical black hole 123. There are 22 sets of Your Turn exercises with answers and a 17-question self-test with answers. Algebra: Numbers 01 is available as a PDF file and also as a Microsoft Word file that you can edit. May dragons of algebraic alakazams be with you.