Copyright © University of Cambridge. All rights reserved. 'How
Safe Are You?' printed from http://nrich.maths.org/ We're going
to look at opening safes! Many have dials on them, and you turn
the dials - as you see in these two pictures - to open them. So
I'll show you a simple dial first with just the numbers $0 - 5$
on it. To open the safe, the dial has to have $2$ next to the
arrow, like The question for you is, how much turning of the
dial did we have to do to get the $2$ at the top? The next safe
we get to has a different dial, it has the numbers $0 How much
turning to get the number $5$ at the top? [Shown in the The
number that you have to get at the top is often called the
"combination" of the safe. These three different safes all start
with $0$ [zero] at the top. You have to find the amount of
turning to get to the combination, shown in each second picture:
Now have a go at these different safes. Remember they would all
start with $0$ [zero] at the top, so, how much turning to get
the required combinat