Here are a couple of free Y3 maths worksheets to challenge children’s knowledge of addition up to 20. I suggest that you take just one set of 10 questions at a time and that a stop watch or clock is used to time how long it takes to answer the questions.
How long should they take? Well, if a child knows their number bonds, not very long at all – certainly less than a minute. Any longer, even if the answers are correct, they are probably counting on rather than knowing. Similar pages are easily created if more practice is needed.