1ST GRADE MATH • NUMBER & OPERATIONS IN BASE TEN

Counting to 120

Learn to count, read, and write numbers from any starting point all the way up to 120!

Where Did Numbers Come From?

A long, long time ago, people did not have numbers the way we do now. They needed to keep track of things like sheep, fish, and bags of food. So they found clever ways to count! Let's look at how counting grew over time.

Very Long Ago
People used tally marks — little lines scratched into bones or sticks. Each line meant "one more." |||| meant four things!
About 5,000 Years Ago
People in a place called Mesopotamia made special shapes in clay to stand for numbers. This was one of the first times people wrote numbers down.
About 2,000 Years Ago
People in India invented the numerals we use today: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. These ten digits let us write any number!
Today
We use those same ten digits to count everything — from crayons in a box to stars in the sky. And right now, you are going to learn to count all the way to 120!

People invented counting because they needed to know "how many?" That is the same question you answer every time you count. When you count to 120, you are doing something humans have worked on for thousands of years!

The Big Ideas of Counting

Before we start counting, let's learn four big ideas. These ideas will help you count all the way to 120 and beyond!

1

We Use Ten Digits

There are only ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. We mix and match these digits to make every number!
2

Numbers Have an Order

Numbers go in order. Each number is one more than the one before it. After 7 comes 8. After 99 comes 100!
3

Ones and Tens

In a two-digit number like 35, the 3 means "3 tens" (thirty) and the 5 means "5 ones." Knowing this helps you count past ten!
4

You Can Start Anywhere

You don't always have to start at 1. You can start counting from any number — like 46, 73, or 108 — and keep going!
Key Takeaway
Think of numbers like the steps on a staircase. You can start climbing from any step, and each new step is one more than the last. The staircase keeps going — 1, 2, 3 … all the way past 100 and up to 120!

The Number Chart to 120

Here is a chart that shows every number from 1 to 120. Each row has ten numbers. Look at how the tens digit changes when you start a new row!

Number chart from 1 to 120 arranged in rows of ten

Look at the chart above. Do you see how each row of ten numbers starts with a new tens digit? The first row goes 1–10. The next row goes 11–20. The pattern keeps going all the way to 120. Every time you reach a number that ends in zero (like 10, 20, 30), the next number starts a brand new set of ten!

This chart is your best friend when learning to count. You can put your finger on any number and count forward. Try it: find 53 and count up to 62. You'll go 53, 54, 55, 56, 57, 58, 59, 60, 61, 62!

How Counting Works

When you count, you say numbers in order. Each number is one more than the last. Let's see how the ones place and tens place work together.

The Ones Place
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
These are the ten digits. They go in the "ones" spot.

When you count from 1 to 9, you only change the ones digit. But what happens after 9? There is no single digit for "ten." So we use two places: a tens place and a ones place.

What Happens After 9
9 → 10
The ones place goes back to 0, and the tens place goes up to 1.

This same trick happens every time the ones place reaches 9. After 19 comes 20. After 29 comes 30. After 99 comes 100! When all the ones are used up, the next bigger place goes up by one.

What Happens After 99
99 → 100
Now we need a hundreds place! The 1 in 100 means "one hundred."

Numbers past 100 work the same way. After 100 comes 101, 102, 103 … and they keep going up to 120 and beyond. You already know the pattern — just keep adding one!

Key Takeaway
Counting is like an odometer on a car (the thing that counts miles). The ones wheel spins from 0 to 9, and then it flips back to 0 while the tens wheel clicks up by one. When the tens wheel hits 9 and flips, the hundreds wheel clicks up. It's the same pattern over and over!

Counting Objects & Writing Numerals

Numbers aren't just for saying out loud. You can also write a numeral to show how many objects there are. A numeral is the written form of a number (like "7" or "43" or "110").

Let's practice. Below are groups of stars. Count each group, then look at the numeral that matches.

Group A

⭐⭐⭐⭐⭐ ⭐⭐⭐

Count them: 1, 2, 3, 4, 5, 6, 7, 8. There are 8 stars. We write the numeral 8.

Group B

🍎🍎🍎🍎🍎 🍎🍎🍎🍎🍎 🍎🍎🍎🍎🍎

Count them: that's 5 + 5 + 5 = 15 apples. We write the numeral 15. The "1" means one ten, and the "5" means five ones.

Diagram showing 23 circles grouped into 2 groups of ten and 3 ones

In the picture above, you can see 2 groups of ten circles and 3 extra ones. That's 10 + 10 + 3 = 23. The numeral 23 tells us exactly how many there are. The "2" stands for 2 tens and the "3" stands for 3 ones.

Whenever you count a group of objects, you can write the numeral that matches. If you count 47 blocks, you write 47. If someone writes the numeral 103, you know there are 103 things.

Worked Example

Let's do a full counting problem together, step by step!

Count from 96 to 110. Write each numeral.
1
Step 1 — Start at 96We begin at 96. The next number is one more: 97.
2
Step 2 — Keep adding one97, 98, 99 … now we're at 99. That's the biggest two-digit number!
3
Step 3 — Cross into the hundredsAfter 99 comes 100. We write a "1" in the hundreds place, and "00" for zero tens and zero ones. Say it: "one hundred."
4
Step 4 — Keep counting in the hundreds100, 101, 102, 103, 104, 105, 106, 107, 108, 109 …
5
Step 5 — Reach 110After 109 comes 110. The ones place went past 9 again, so the tens place went up! We're done.
Our Answer
96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110

Great job! Notice how we didn't have to start at 1. We started right at 96 and counted up. You can start at any number less than 120 and keep going.

Tips, Tricks & Tricky Spots

Counting to 120 is fun, but some parts can be tricky! Here are the spots where kids sometimes get mixed up, and tips to help you get it right every time.

Tricky SpotWhat Goes WrongTip to Fix It
After 19Some kids say "twenty-ten" instead of 20.Remember: after 19, the tens digit goes to 2 and the ones reset to 0. That's 20!
The teens (11–19)The names sound funny — "eleven," "twelve," "thirteen" don't follow a clear pattern.Practice saying them often. These are special names to memorize.
After 99Going from 99 to 100 feels like a big jump.It's the same pattern! The ones and tens both reset, and a new hundreds place starts.
After 109Some kids write "1010" instead of 110.110 = one hundred ten. The "11" part means 11 tens, not "ten-ten."
Skipping numbersIt's easy to skip a number when counting fast.Point to each object as you count. Touch it and say the number!
Key Takeaway
Counting is like climbing monkey bars. If you skip a bar, you might fall! Touch each object one at a time and say the number. That way you won't skip any or count one twice.

What Comes Next?

Once you can count to 120, you're ready for some really exciting math! Here's a peek at what you'll learn soon.

What You Know NowWhat You'll Learn Next
Count to 120Count to 1,000 and even higher!
Read & write numerals like 73Compare numbers: Is 73 more or less than 68?
Know ones and tensLearn the hundreds place and what each digit really means
Count one by oneSkip count by 2s, 5s, and 10s to go faster!

Everything you learn today is the foundation for all the math you'll ever do. Addition, subtraction, multiplication — they all start with counting. You're building the base of a very tall tower!

Practice Problems

Try these problems on your own. When you're ready, click "Show Answer" to check your work!

PROBLEM 1WHAT COMES NEXT?
What number comes right after 79?
PROBLEM 2COUNT FROM A NUMBER
Start at 57 and count up to 65. Write every numeral.
PROBLEM 3HOW MANY OBJECTS?
Count the hearts below and write the numeral: ❤️❤️❤️❤️❤️ ❤️❤️❤️❤️❤️ ❤️❤️❤️❤️❤️ ❤️❤️❤️❤️❤️ ❤️❤️
PROBLEM 4REAL-WORLD COUNTING
Emma has 108 stickers. She gets 5 more stickers from her friend. She counts them all. What numbers does she say as she counts the new stickers? What is the last number she says?
PROBLEM 5THINK ABOUT IT
Jake says: "The number after 100 is 200 because after 1 comes 2." Is Jake right? Why or why not?

Let's Review!

You learned that we use ten digits (0–9) to write every number. Numbers go in order, and each one is one more than the last. When the ones place fills up past 9, it resets to 0 and the tens place goes up by one. The same thing happens when the tens fill up — that's when we reach 100 and start using the hundreds place.

You can start counting at any number less than 120 and count forward — you don't have to start at 1. You can also read and write numerals to show how many objects there are. If you see 15 blocks, you write the numeral 15. If you read the numeral 107, you know that means one hundred seven things. Keep practicing, and you'll be a counting champion! 🌟

Varsity Tutors • 1st Grade Mathematics (Common Core) • Counting to 120