Education Technology

Fast Facts

Published on 03/01/2017

Activity Overview

This activity is an extension of the Factors that Count activity and Counting Factors Coding exercise.  STEM principles involve designing, testing and evaluating.  In this exercise students evaluate the efficiency of the Counting Factors program and through small changes in the code and some basic number facts students dramatically improve the efficiency.


Apply STEM principles Design /Test / Evaluate to improve coding efficiency by utilising some basic number facts.



  • Factor
  • Prime
  • Composite
  • Even / Odd


  • IF / Then/ Else
  • For/ Endfor
  • Mod
  • Int

About the Lesson

The factors that count activity requires students to explore the prime factorisation of a number and the corresponding quantity of factors. Students can use a pre-prepared program, alternatively they can produce the program themselves using the Counting Factors exercise and then apply STEM principles Design – Test – Evaluate to dramatically improve the efficiency of the program. In FAST FACTS students consider whether or not all numbers less than the selected number need to be tested as factors. Students use the idea of factor pairs to check numbers up to the square root of the selected number. Another efficiency improvement is to check if the original number is even, if it isn’t, then the FOR loop can start at 1 and step by 2: 1, 3, 5, 7 … since no other even numbers will be a factor.