Chapters 11-14

Chapter 11

oeisLink: Online Encyclopaedia of Integer Sequences

The OEIS is an invaluable reference for anyone wanting to find out about sequences of integers. Type in the first few terms to see which sequences start with them or type in the name of a sequence to find it in the database. Look up your birthday! Or, you know, use it for serious mathematical research.
Online Encyclopaedia of Integer Sequences (website)

Toy: Combination Calculator

Are you faced with a pile of M things from which you need to choose N? We’ve all been there. And this handy calculator will tell you exactly how many options you have. (Full version)

choose = {{combinations(a, b)}}
{{a}} pick {{b}} = {{permutations(a, b)}}
{{a}}! = {{factorial(a)}}

Link to this result

Chapter 12

dominoLink: Domino computer worksheets

Put your spare dominoes to good use doing some incredibly slow calculations. Over at Think Maths (my education site) I have a great selection of worksheets outlining how to build different domino logic gates, so you can give it a try!
Think Maths Domino Computer Worksheets (website)

Chapter 13

Matt’s Python code

It’s not pretty and it’s not efficient, but here is my python code for finding grafting numbers is below. I wrote it when I was learning Python as a hobby. If you know how to run Python code, you can use it to find grafting numbers for yourself!
Click to show/hide Matt’s code