When they start school, they will learn about 10s and units and explore concepts such as addition, subtraction and place value. They will use number lines to help them count on from a given number.
At some point, children will need to make the leap from using props to using mental arithmetic for basic addition. Here are three maths strategies you can help your child with:
Counting on from a given number is generally the first stage in mental arithmetic. In the beginning, children will start everything from the number one. It is relatively easy for them to add together 3 and 4 because they can hold up three fingers on one hand, four on the other and then count up all the fingers. But once they are tackling, say 6 + 7, they run out of fingers and get stuck.
Using the ‘counting on’ strategy (instead of ‘counting all’), a child will identify the biggest number in a sum as their starting point (5, in the example below) and then ‘count on’ the other number from there (often using their fingers!).
Doubles and near-doubles
5 fingers on the left hand + 5 fingers on the right hand = 10 fingers altogether
2 front legs + 2 back legs = 4 legs on a cow
6 eggs + 6 eggs = 12 eggs
Children are surrounded by doubles in their everyday life, so learning 1 + 1 and 2 + 2 etc comes quite easily. Once they know their doubles, they no longer have to think about the equation to solve it; they will automatically know that 7 + 7 = 14 without having to count.
When a child knows their doubles well, it is not a big leap to solve sums that are close to doubles, e.g. 4 + 5 is one more than 4 + 4.
Memorising the number combinations that add to 10 gives children more automaticity in their mental arithmetic. Once they recognise that 7+3, 6+4, 5+5, 8+2 and 9+1 equal 10, they will spend less time counting on their fingers; they will ‘know’ these combinations without having to work them out. When a child knows that 8+2 equals 10, it is easy to work out 8+3 or 8+4. Knowing the number bonds that make 10 also removes the need to ‘count on’ in some situations.
This article is an extract from a King’s Christian College blog post. For more details and ideas, search in Google for “King’s Christian College maths addition strategies.”