Place Value: Tens and Ones (Introduction to 20)

Free sample questions, a clear explanation, and 5 practice skills with an AI tutor that guides without giving the answer away.

Let's Build Numbers with Super Teams of Ten! 🚀

Hey, Math Explorer! Have you ever tried to carry a big pile of crayons? It’s tricky! But what if you put them into a crayon box? It’s so much easier! Counting big numbers is just like that. We use a special "box" that holds exactly ten things. This makes counting super fast and organized!

Let's pretend our crayon box holds 10 crayons. When the box is full, we call it a "ten." Any crayons left outside the box are called "ones."

So, if you have one full box and 4 loose crayons, you have 1 ten and 4 ones. Put them together, and you have the number 14! See? The '1' in 14 tells us we have one full group of ten, and the '4' tells us we have four extra ones.

Building Our Teen Numbers

All the numbers from 10 to 19 are called "teen" numbers, and they all have one "team of ten" in them. Think about it like this:

12 is 1 group of ten and 2 extra ones.
15 is 1 group of ten and 5 extra ones.
18 is 1 group of ten and 8 extra ones.

This is called place value! It means that where a digit is in a number tells us how much it's worth. In the number 17, the 1 is in the "tens place" and the 7 is in the "ones place."

Key Takeaway! 🌟

Numbers bigger than 9 are made of groups of tens and some extra ones. The number 13 isn't a 1 and a 3, it's a 1 ten and a 3 ones!

What About 20?

So what happens if we have 1 ten and 9 ones (that's 19!) and we find one more crayon? Hooray! Now we have 10 loose crayons, which means we can fill a whole new box! We now have TWO full boxes and ZERO loose ones. That gives us the number 20! Two groups of ten make twenty.

You are doing an amazing job building these big numbers. Keep spotting those teams of ten everywhere you go!

Sample questions

1. Look at the apples. How many apples are there in total? 🍎🍎🍎🍎🍎🍎🍎🍎🍎🍎 🍎🍎🍎

○ 3

✓ 13

○ 10

○ 31

Answer: 13 — Count the group of ten first, then count the extra ones.

2. How many stars do you see? ⭐⭐⭐⭐⭐⭐⭐⭐⭐⭐ ⭐⭐⭐⭐⭐⭐⭐

○ 7

○ 10

✓ 17

○ 71

Answer: 17 — A group of ten and some more.

3. Count the balloons. What number do they show? 🎈🎈🎈🎈🎈🎈🎈🎈🎈🎈

✓ 10

○ 1

○ 0

○ 11

Answer: 10 — Remember, a full group is ten.

Skills in this topic

Group objects into tens and ones to represent numbers up to 20.
Identify the value of digits in numbers up to 20 (e.g., 1 ten and 3 ones make 13).
Represent numbers up to 20 using place value charts and base-ten blocks.
Decompose numbers up to 20 into tens and ones (e.g., 17 is 1 ten and 7 ones).
Explain how the number of tens and ones changes when counting from 10 to 20.

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