Place four pebbles on the sand in the form of a square. Keep adding
as few pebbles as necessary to double the area. How many extra
pebbles are added each time?
Make a set of numbers that use all the digits from 1 to 9, once and
once only. Add them up. The result is divisible by 9. Add each of
the digits in the new number. What is their sum? Now try some other
possibilities for yourself!
For this challenge, you'll need to play Got It! Can you explain the
strategy for winning this game with any target?
The total number they were using must be divisible by $3$.
Ben's counters must initially have been divisible by $3$, Jack's
by $4$ and Emma's by $5$.
It might help to work out the maximum each could have started
with - e.g. Emma could not have started with $25$ counters. Can you
work out why?
How many counters could each of them have started with?
Try some possible numbers.