Subitising is the ability to look at a small number of objects and instantly recognise how many objects there are without needing to count.
In early years, children look at tally marks, how many fingers are being held up or the dots on dice to help develop this skill.
There are two types of subitising: perceptual and conceptual.
Our brains can only easily subitise numbers up to five – this is perceptual subitising. Anything above five is conceptual subitising. This is because the numbers then start to relate to a larger quantity of things and identifying ‘how many’ without counting becomes more difficult.
For example, to subitise six, we would need to subitise three and three; four and two; or five and one. Only then could we combine the number pairs together to arrive at an answer of six.
Subitising is essential for children’s mathematical development for many reasons:
Subitising is an alternative strategy which is more efficient when dealing with smaller numbers. It helps children to see how numbers are made up. For example, you can make the number eight using many pairs: 1 + 7, 2 + 6, 3 + 5 and 4 + 4. By separating and combining numbers through subitising, children lay the foundations for addition and subtraction.
Children also learn an important mathematical law through subitising: it doesn’t matter in what order you add numbers together – you always get the same answer! For example, 2 + 3 = 5 and 3 + 2 = 5.
You don’t need to spend lots of money to help your child with subitising. Here are a few ideas:
Board games with dice are a great way to have fun and sneak some subitising in! Give your child a number and ask them to show you the number using their fingers. To make this harder, ask them to show you in different ways.
For example, five can be represented by five fingers on one hand or three fingers on one hand and two fingers on the other. Why not check out thesemathematical board games to get started!
Make some flashcards that show dot patterns, tally marks and fingers being held up (if you are feeling creative!). Can your child tell you how many there are without counting? To make this harder, show them a flashcard for only a few seconds and then hide it! This encourages them to subitise rather than count.
Throw a small number of counters in two different colours on the table and ask your child to say what they see. For example, “I see three red counters and two yellow counters. There are five counters altogether”. You don’t have to use counters either – there are plenty of alternatives that would suffice!