QLD should not be behind NSW anymore. Students already in highschool may be, but not those in early primary school. That is why the prep year was introduced in QLD.

By year 3 they really should understand odds and evens and basic multiplication. Having said that, your son will not be the only one struggling with the naplan practice Qs. Naplan is hard. It is a format that doesn't really work well for young children and this is why so many teachers hate it. They will spend lots of time getting the students used to doing Qs like they will encounter on naplan, even if it isn't the best way to be teaching the students, because if the school does badly on naplan then they look bad on myschool and parents judge schools using that information.

All you can do is work on that basic stuff with him at home as much as you can, because he needs to understand it now so that he doesn't struggle all the way through school.