Numbers 10 to 20
After 9, we start using two-digit numbers. The numbers from 10 to 20 are called teen numbers (except 10 and 20).
Each of these numbers is made of a ten and some ones. For example, 13 = 1 ten + 3 ones.
What is Numbers 10 to 20 - Class 1 Maths (Numbers 10 to 20)?
Numbers 10 to 20 are the first set of two-digit numbers. They all have 1 ten in them.
| Number | Tens | Ones |
|---|---|---|
| 10 | 1 | 0 |
| 11 | 1 | 1 |
| 12 | 1 | 2 |
| 13 | 1 | 3 |
| 14 | 1 | 4 |
| 15 | 1 | 5 |
| 16 | 1 | 6 |
| 17 | 1 | 7 |
| 18 | 1 | 8 |
| 19 | 1 | 9 |
| 20 | 2 | 0 |
Solved Examples
Example 1: Count from 10 to 20
Question: Count forward from 10 to 20.
Think:
- Start at 10, add one each time
10 — 11 — 12 — 13 — 14 — 15 — 16 — 17 — 18 — 19 — 20
Answer: The numbers from 10 to 20 are shown above.
Example 2: How Many Tens and Ones in 14?
Question: Break 14 into tens and ones.
Think:
- 14 has 1 group of ten and 4 ones left over
- 1 ten + 4 ones = 14
Answer: 14 = 1 ten and 4 ones.
Example 3: What Comes After 16?
Question: What number comes after 16?
Think:
- 16 + 1 = 17
Answer: 17 comes after 16.
Example 4: What Comes Before 20?
Question: What number comes just before 20?
Think:
- 20 − 1 = 19
Answer: 19 comes just before 20.
Example 5: Ria's Stickers
Question: Ria has 10 stickers. She gets 5 more. How many stickers now?
Think:
- Start at 10, count on 5 more: 11, 12, 13, 14, 15
- 10 + 5 = 15
Answer: Ria has 15 stickers.
Example 6: Between 11 and 13
Question: What number is between 11 and 13?
Think:
- 11, ?, 13
- After 11 comes 12
Answer: 12 is between 11 and 13.
Example 7: Count Backward from 20
Question: Count backward from 20 to 15.
Think:
- Start at 20 and subtract 1 each time
20 — 19 — 18 — 17 — 16 — 15
Answer: 20, 19, 18, 17, 16, 15.
Key Points to Remember
- Numbers 10 to 20 are the first two-digit numbers.
- All these numbers have 1 ten (except 20, which has 2 tens).
- 10 = 1 ten + 0 ones. 20 = 2 tens + 0 ones.
- Numbers 11 to 19 are called teen numbers.
- Each number is one more than the number before it.
- After 19 comes 20 (a new group of tens).
Practice Problems
- Count from 10 to 20 and write all the numbers.
- How many tens and ones in 17?
- What number comes after 18?
- What number comes before 14?
- Fill in: 12, 13, ___, 15.
- Aman has 10 toy cars. He buys 8 more. How many now?
Frequently Asked Questions
Q1. What are the numbers 10 to 20?
They are: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20. These are the first two-digit numbers a child learns.
Q2. Why are 11 to 19 called teen numbers?
Most of them end in "-teen": thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen. Eleven and twelve have special names.
Q3. How many tens are in 15?
15 has 1 ten and 5 ones. All numbers from 10 to 19 have exactly 1 ten.
Q4. What number comes after 19?
20 (Twenty) comes after 19. It has 2 tens and 0 ones.
Q5. How is 10 different from 1?
1 is a single-digit number with just 1 one. 10 is a two-digit number with 1 ten and 0 ones. 10 is ten times bigger than 1.
Q6. How do I count from 10 to 20?
Start at 10 and add 1 each time: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.
