Here's a help for either checking or to set you thinking about further explorations.
So, if we saw 1 in the unmasked window then these would be the possibilities:
Plenty to explore here!
Pupils can explore all kinds of things around these five different counting methods.
You can arrange a whole period of time for being a Threebee. For example calculating and saying and recording all numbers in that style.
These different ways of counting are also known as "bases". We use base 10, and many things connected with electrical engineering use base 2.