Numbers up to 20
Primary 1 · Mathematics
Numbers up to 20
Lesson 2 of 7
12 min
Let's begin
Uwase sits with her slate at school.
The teacher says one word: fourteen.
Uwase hears four first. So she writes 41.
The teacher shakes her head kindly. Today you will learn where the 1 goes.
Take one bundle of 10 sticks. Hold it in one hand.
Put 1 loose stick beside it. That is 11, eleven.
Put 2 loose sticks beside it. That is 12, twelve.
Keep adding one loose stick at a time.
| Sticks | Number | Name |
|---|---|---|
| 1 bundle and 1 | 11 | eleven |
| 1 bundle and 2 | 12 | twelve |
| 1 bundle and 3 | 13 | thirteen |
| 1 bundle and 4 | 14 | fourteen |
| 1 bundle and 5 | 15 | fifteen |
Every one of these numbers starts with 1. That 1 is the tied bundle.
The word fourteen says four at the start.
But the bundle of ten is written first on the page.
Worked example
write fourteen.
Step 1 Fourteen is 1 ten and 4 ones.
Step 2 Write the tens digit: 1.
Step 3 Write the ones digit beside it: 4.
You have written 14.
Careful! 14 and 41 use the same two digits. They are not the same number.
41 is four whole bundles and 1 loose stick. That is far too many.
Say thirteen (13). Now say thirty (30). The two words sound close.
Teen means one ten and some ones. A teen number is small. It is under 20.
13 is 1 bundle and 3 loose sticks.
30 is 3 whole bundles. That is much bigger.
When you hear teen at the end, begin your writing with 1.
Mugisha counts 13 beans into a cup. Count 13 beans into a cup too.
Tip
The 1 in front is the tied bundle
Hear a teen? Write the 1 first. Then write the ones you heard.
Did you write 41 for fourteen? Your pencil followed your ear.
Put the bundle first, every time.
Count 11 to 15 with Akili.
Do each one, then tap Show answer to check.
Write twelve as a number.
Answer: 12. One ten and 2 ones.
Write fifteen as a number.
Answer: 15. Write the 1 first, then the 5.
Mugisha has 1 bundle of ten and 3 loose sticks. How many sticks?
Answer: 13. Start on 10, then count 11, 12, 13.
Read this number out loud: 11.
Answer: eleven. One ten and 1 one.
Keza wrote 31 for thirteen. What should she write?
Answer: 13. The tied bundle is written first.
What you learned today
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