Year 3 addition and subtraction – missing digits Children in Year 3 are now expected to add and subtract using the formal written method. An interesting way of looking at this is to show various calculations using the written method but have some of the digits missing. To be able to find the missing digits children will need to have a very good grasp of the formal written method and the worksheets are a great way to introduce some variety into this aspect of calculating. There are three sets of addition of increasing difficulty, using 2-digit numbers, with the third set including bridging in both columns. There are also three sets of subtraction using 2-digit numbers. Go to Addition: missing digits Go to Subtraction: missing digits