DD2 is doing the same as Onyx's DS. They also play a lot of interactive maths games on the computer when they have finished their other maths work. They are called Targeting Math (can get them from fishpond, boomerang books or dymocks) and they go up to year 6. The one for Kindergarten is pretty basic and DD has mastered it all, so she does the year 3 one I have only because I haven't got the year 1 and 2 ones yet. So that is an alternative if he's not keen on writing things down or using a book. Also go to a bookshop or look online for all the educational workbooks. I have gotten a few for DS1 that they are using in class to use at home to supplement what he does in class. One of them was the Targeting Maths one that compliments the CD and written by Garda Turner - it is for NSW but you can get them for the VIC curriculum. I also have the Excel and Oxford Primary Mathematics (author is Pat Lilburn) ones. Now all of those books have a teachers resource book, so I think you should get one of those just so you know what the curriculum is, how to teach it and it gives you a complete program to follow as well as lesson plans.

If he loves his maths, then nurture that as much as you can so it is not such a big deal when you want to switch over and do a bit of literacy. Also turn the maths into a literacy lesson by getting him to help read out the maths problems etc as well. Go to your library and see what they have available in simple first readers - most of what they bring home are just simple readers at this stage and your library should have loads of them. At this stage they still learn sounds using phonics, so any phonics-based stuff should be fine as well.