Here's a useful printable poster / chart showing how red and yellow make orange, red and blue make purple, and yellow and blue make green. Laminate it and keep it handy, and use it with our colour mixing worksheets.
Colour Mixing Chart
Kids will enjoying having a go at these colour "sums" on this bright and cheerful colour mixing worksheet! UK and US versions available below.
Which two primary colours do you need to mix together to create the secondary colour shown? Grab a set of crayons and fill in the worksheet...