Practice makes perfect, and this is very true with mental addition of numbers. Hence we include another page of mental arithmetic; this time it is addition of three 2-digit numbers. All the numbers to be added are in the teens. This is one of those pages where it is well worth asking children how they went about working out the answers as there are a number of different skills needed to work quickly and efficiently. For example: look for pairs that make 30 (e.g. 14 = 16) look for pairs that nearly make whole tens and adjust (e.g. for 29 + 13  work out 30 + 13 and adjust by one) start with the largest number look for doubles that are known (e.g. 15 + 15 = 30) Children who use a variety of techniques are showing high level skills of addition. Of course a correct answer is better than a fast answer which is incorrect, so encourage checking by adding the numbers in a different order. This page can be found in our Year 5 Addition category, together with many others. Go to More practice adding three 2-digit numbers