๐ข Understanding Numbers 11-19
Numbers 11 through 19 are special because they're made up of one group of ten and some extra ones! Think of it like having a full box of ten crayons ๐๏ธ and then a few more crayons that didn't fit in the box.
๐๏ธ A Little Number History
Our number system, including the way we group numbers into tens and ones (also called the base-ten system), comes from ancient times. It's believed to be related to the fact that we have ten fingers! Over centuries, this system spread and evolved, making it easier to count and do math. This system allows us to represent any number, no matter how big, using just ten digits (0-9).
๐งฑ Key Principles: Tens and Ones
- ๐ The 'Ten' Place: This place tells you how many groups of ten you have. In numbers 11-19, the 'ten' place is always 1, meaning one group of ten.
- โ The 'Ones' Place: This place tells you how many single ones you have left over after making a group of ten. For example, in the number 13, you have three ones.
- ๐ก Putting it Together: The number is then the sum of the value in the tens place and the ones place. So, $13 = 10 + 3$.
โ๏ธ Writing Numbers 11-19 as Tens and Ones
Let's break down each number:
- ๐ 11: 1 ten and 1 one. $11 = 10 + 1$
- ๐ 12: 1 ten and 2 ones. $12 = 10 + 2$
- ๐ 13: 1 ten and 3 ones. $13 = 10 + 3$
- ๐ 14: 1 ten and 4 ones. $14 = 10 + 4$
- ๐ 15: 1 ten and 5 ones. $15 = 10 + 5$
- ๐ 16: 1 ten and 6 ones. $16 = 10 + 6$
- ๐ฅ 17: 1 ten and 7 ones. $17 = 10 + 7$
- ๐ฅ 18: 1 ten and 8 ones. $18 = 10 + 8$
- ๐ 19: 1 ten and 9 ones. $19 = 10 + 9$
๐๏ธ Real-World Examples
- ๐งธ Toys: Imagine you have a box with 10 toy cars ๐ (1 ten) and 3 extra toy cars outside the box (3 ones). You have 13 toy cars in total!
- ๐ช Cookies: You baked a batch of cookies! You have 10 cookies on a plate (1 ten) and 6 more cookies cooling on the counter (6 ones). You baked 16 cookies!
- ๐ Books: Your bookshelf has one stack of 10 books (1 ten) and 8 single books next to it (8 ones). You have 18 books!
โ๏ธ Practice Quiz
Let's test your skills! Can you identify the tens and ones in these numbers?
| Number |
Tens |
Ones |
| 14 |
1 |
4 |
| 17 |
1 |
7 |
| 11 |
1 |
1 |
| 19 |
1 |
9 |
| 13 |
1 |
3 |
| 16 |
1 |
6 |
| 12 |
1 |
2 |
โญ Conclusion
Great job! ๐ You've now learned how to break down numbers 11-19 into tens and ones. Keep practicing, and you'll become a number expert in no time!