Four 4s

Introduction

Look at the question on the right. Believe it or not the answer is NOT 5!

Why isn't the answer 5? Hint: take a look at this video.

In today's lesson you are tasked with finding every number between 1 and 20 using only four 4’s and any operation. Not sure how? Look at this video to get you started.

Further Practice

Still not sure what to do? Maybe you need to review the order of operations first. Take a look at this video - this Maths problem went viral on Twitter and there has been debate about the answer. Presh explains why one interpretation is considered correct.

Take this opportunity to brush up on BIDMAS a.k.a order of operation. Do the relevant skills practice on DrFrostMaths, CorbettMaths, MyiMaths and Eedi. Watch any video and/or go through any online lesson as you see fit.

If you are already quite confident, try these harder questions from taylorda01 and mrdaper:

Further Questions and Challenges

Try this Bidmaze puzzle! Find your way through the maze encountering mathematical operations in the correct order to achieve the given total.

Finding this too easy, why not try 54321 puzzle?

Or you may wish too look at the puzzles by Don Steward:

Extension

Take a look at how this physics genius solved the 'four 4s' problem all the way to infinity here (warning: this requires mathematics way beyond what you need to know for year 7!)