One numeral for each count
Count the squares, touching each one once: 1, 2, 3, 4, 5, 6, 7. There are seven squares, and the count is written with the numeral 7.
There are ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. Every count from nothing up to nine is written with just one of them.
Seven squares. The count is written 7.
A full ten and some more
After 9 there are no more digits. So once a count reaches ten, the ten squares are kept together as one ten, and the number is written with two digits: the first counts the tens, and the second counts the ones left over.
Thirteen squares are one full ten and 3 more. The number is written 13: the 1 counts the ten, and the 3 counts the 3 loose squares. Ten squares on their own are one ten and no ones, written 10.
A full ten and 3 more squares. The number is written 13.
fewer than ten ones: the ones digit counts them, the tens digit is 0, and 10 = 1 ten is not yet reached
Drop ten ones, then drag the bundle into the tens column
Drop ones into the ones column until there are ten or more, then drag the bundle of ten across. The ten loose ones become one ten, and the two columns show the two digits of the number.
Said ones first, written ten first
The words for the teens can trick you. Fourteen says the four first, but 14 is written with the 1 for the ten first and the 4 for the ones after it. Writing the 4 first makes 41, which is a much bigger number.
Every number from 11 to 19 starts with 1, because each is one full ten and some more. The second digit says how many more: 16 is one ten and 6 ones.
Two full tens
Twenty squares make two full tens with nothing left over. The number is written 20: the 2 counts the two tens, and the 0 says there are no loose ones.
The 0 matters. Without it the number would be 2, which forgets that each ten holds ten squares.
Two full tens and nothing left over. The number is written 20.
Worked example: A Box of Ten Pencils and Some Loose Pencils
Question There are 10 pencils in a box. There are 4 loose pencils beside the box. (a) How many pencils are there altogether? (b) Ben writes the number. He writes 1 first for the one ten. What does he write next?
1.Draw a ten frame that is full. It is the box of 10 pencils.
The full ten frame is the box of 10 pencils. 2.Draw 4 counters beside the frame for the 4 loose pencils.
There are 4 counters beside the frame for the 4 loose pencils. 3.(a) Count on from 10: 11, 12, 13, 14. There are 14 pencils altogether.
(a) Count on from 10: 11, 12, 13, 14. There are 14 pencils altogether. 4.(b) The number 14 is one ten and 4 ones. Ben writes 1 for the ten, and then he writes 4 for the ones.
(b) The number 14 is one ten and 4 ones. Ben writes 1 for the ten, and then 4 for the ones.
Answer: (a) 14 pencils; (b) 4
Common mistakes
- Saying 10 again for the first loose pencil and ending at 13. The box is 10 already, so the first loose pencil is 11.
- Writing the 4 first and then the 1, which is 41. The ten is written first and the ones are written after it, so the number is 14.