The purpose of this unit is to recognise and understand teen numbers. This is an essential piece of knowledge for the part-whole strategy of bridging to ten.
recognise and understand “teen” numbers, 11-20.
Advanced Counting (Counting on)
Pre-requisite knowledge / skills: form addition facts to ten using dot patterns on a quinary frame
Teacher hold up a full tens frame and asks
How many have I got?
- Teacher holds up another card, alongside the full tens frame, and asks
How many have I got now?
- Repeat several times ensuring that the numbers 11 – 20 have been covered.
- Teacher repeats above but this time shows the students the full tens frame has been turned over so the dots are not visible.
- Teacher models 11 on the tens frame.
Let’s look at the number 11. How would we write that?
Records: 10 + 1 = 11 then works through 10 + 2 = 12, 10 + 3 = 13 etc similarly to show the pattern.
- Teacher asks students to solve problems such as 10 + 4, 10 + 9 with a focus on quick recall.
Teacher models one of the teen numbers on a tens frame. Students record the written form “15” while one student uses the expanded numeral cards to record the number. Once the recording is finished teacher asks:
What does the 1 mean? [1 group of ten]
What does the 5 mean? [ 5 ones]
Teacher adds further blank tens frames to the model, for example 21: two tens and a 1.
Note: the context of a train with one full carriage and one partly full carriage can be used in this teaching sequence