If you don't have a printer you could try drawing around some different boxes and tins. Cut out the shapes, then fold your shapes in half and cut them again. Stick the shapes in your maths books and label the halves. Use the word half or write it as a number. Like this...
If you'd prefer an online game. Try this halving game called Hit the Button
Hit the ButtonThe first three games will be most suitable for you, but feel free to try any of them.