Once your child has learned to count and recognise numbers to 20 (see Book 7), and has learned to add and take away to 10 (see Book 5), they can then learn to focus on adding and subtracting with totals of up to 20. In Excel Maths Early Skills: Add and Take Away to 20, your child will: - revise adding and subtracting to 10. - learn to add and subtract numbers to 20. - become more confident with using numbers to 20.