Numbers to twenty
Maths · Early Years · The School
Counting past ten
After ten come eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen and twenty. Eleven and twelve are the awkward ones because they do not sound like the numbers they contain. From thirteen onwards the pattern helps: THREE-teen, FOUR-teen, FIVE-teen and so on.
One number for each thing
When you count objects, you say ONE number for each thing, and the last number you say is how many there are altogether. Counting the same thing twice, or skipping one, gives the wrong answer. Touching or moving each object as you count is what keeps it honest.
Which is bigger
The further along the counting order a number is, the bigger it is. Fifteen comes after eleven when you count, so fifteen is bigger. A number line on the wall makes this visible: bigger numbers are further to the right, and you can see the gap between two numbers rather than just being told it.
Both are teens, so you cannot decide by how they look. Count out loud: eleven, twelve, THIRTEEN, fourteen, fifteen, sixteen, SEVENTEEN. Seventeen came later, so seventeen is bigger. Check on a number line: 17 sits further to the right. Check with cubes: build 13 and 17 and stand them side by side — the 17 tower is four cubes taller. Counting order, number line, objects: three ways, and they always agree.