Cong from St Peter's Roman Catholic Primary School sent in solutions to both parts of this problem. Cong sent us pictures of his completed Venn diagrams. Here is the first:
And here is the second:
I am interested in where you have placed zero in both Venn diagrams, Cong. It is difficult to say whether 0 is odd or even - I can see why you have placed it as an even number, though, as it seems to extend the pattern $8, 6, 4, 2, ... 0$. It's easy to forget that $0$ is a square number - but certainly $0 \times 0=0$.
Michael from Kings Elementary School explained a bit how he went about filling in the first Venn diagram. Michael assumes that 0 is not a square number:
Well done! Eliza, from Danebank School, also left $0$ out of the Venn diagram. What do you think? Is $0$ square and even?