🔹 1. Introduction
In this chapter, students learn numbers from 10 to 20, how to count, write, and compare them.
It helps them move from single-digit numbers (1–9) to two-digit numbers (10–20).
🔹 2. Understanding “Tens” and “Ones”
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All numbers from 10 to 20 have two digits.
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The first digit shows tens, and the second digit shows ones.
👉 Example:
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10 = 1 ten + 0 ones
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12 = 1 ten + 2 ones
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15 = 1 ten + 5 ones
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20 = 2 tens + 0 ones
💡 Tens and Ones Table
| Number | Tens | Ones | Expanded Form |
|---|---|---|---|
| 10 | 1 | 0 | 10 = 10 |
| 11 | 1 | 1 | 10 + 1 |
| 12 | 1 | 2 | 10 + 2 |
| 13 | 1 | 3 | 10 + 3 |
| 14 | 1 | 4 | 10 + 4 |
| 15 | 1 | 5 | 10 + 5 |
| 16 | 1 | 6 | 10 + 6 |
| 17 | 1 | 7 | 10 + 7 |
| 18 | 1 | 8 | 10 + 8 |
| 19 | 1 | 9 | 10 + 9 |
| 20 | 2 | 0 | 10 + 10 |
🔹 3. Number Names (in Words)
| Number | In Words |
|---|---|
| 10 | Ten |
| 11 | Eleven |
| 12 | Twelve |
| 13 | Thirteen |
| 14 | Fourteen |
| 15 | Fifteen |
| 16 | Sixteen |
| 17 | Seventeen |
| 18 | Eighteen |
| 19 | Nineteen |
| 20 | Twenty |
🔹 4. Counting Objects (10–20)
Children count items like:
🧸 Toys, 🍎 Apples, 🎈 Balloons, 🐦 Birds, etc.
👉 Example:
There are 13 apples.
→ 1 ten (10) and 3 ones (3)
→ Total = 13 apples.
🔹 5. Before, After, and Between Numbers
| Type | Example |
|---|---|
| Before | The number before 13 is 12. |
| After | The number after 13 is 14. |
| Between | The number between 12 and 14 is 13. |
🔹 6. Comparing Numbers
We use symbols to compare:
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> means greater than
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< means less than
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= means equal to
👉 Examples:
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15 > 13 (15 is greater than 13)
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11 < 19 (11 is less than 19)
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14 = 14 (equal)
🔹 7. Practice with Objects
| Picture Example | Number | Words |
|---|---|---|
| 🍎🍎🍎🍎🍎🍎🍎🍎🍎🍎 | 10 | Ten apples |
| 🧸🧸🧸🧸🧸🧸🧸🧸🧸🧸🧸🧸 | 12 | Twelve toys |
| 🎈🎈🎈🎈🎈🎈🎈🎈🎈🎈🎈🎈🎈🎈 | 14 | Fourteen balloons |
🔹 8. Missing Numbers (10–20)
👉 Fill in the blanks:
10, 11, ___, 13, 14, ___, 16, 17, ___, 19, 20
✅ Answers: 12, 15, 18
🔹 9. Smallest and Greatest Numbers (10–20)
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Smallest number: 10
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Greatest number: 20
🔹 10. Fun Activity Ideas
🎯 Count 15 pencils in your pencil box.
🎯 Find 12 books on your shelf.
🎯 Draw 10 stars and 8 flowers — count total objects.
🎯 Make number cards from 10 to 20 and arrange in order.
🔹 11. Practice Exercise
| No. | Question | Answer |
|---|---|---|
| 1 | What comes after 12? | 13 |
| 2 | What comes before 16? | 15 |
| 3 | Fill in the blank: 14, __, 16 | 15 |
| 4 | Write in words: 18 | Eighteen |
| 5 | Write in numbers: Fifteen | 15 |
| 6 | 13 < 17 — True or False? | True |
| 7 | How many tens in 19? | 1 ten |
| 8 | How many ones in 19? | 9 ones |
| 9 | 10 + 8 = ? | 18 |
| 10 | Which is greater — 12 or 14? | 14 |
🔹 12. Quick Revision
✅ Numbers from 10 to 20 are two-digit numbers.
✅ They have 1 ten and some ones.
✅ We can write them in words and numbers.
✅ Practice counting, comparing, and ordering these numbers.