Published February 2011.
This question has been very well answered - thank you
to everyone who sent us solutions.
D, J and M from Year 5 and B, H and He from Year 4 at
St. Nicolas CE Junior School, Newbury explain how they tackled
"We listed the prime numbers up to 100 and then we
listed the squares of the numbers between 4 and 20. Then we started
working out the answers by adding two prime numbers together to
make the squares until we reached 400. We found out that two
squares were impossible to make. When we had an odd square number,
we had to have a number that adds on to 2 to make the square number
and sometimes this number wouldn't be prime. For example, to make
121 with two primes, one of the primes has to be 2, and 119 is not
Our results were: