UKMT Senior Kangaroo 2021

A tough paper Prime factor decomposition of big numbers:    • Encryption and HUGE numbers - Numberphile   Eulerian paths:    • The Seven Bridges of Königsberg - Numberphile   Pythagoras with any shape:    • A Pythagorean Theorem for Pentagons + Eins...   How many factors a number has, or how many numbers have a given number of factors:    • Video   The choose functions:    • Combination formula | Probability and comb...