Count To 100 By Ones And Tens — CCSS.K.CC.1: Count to 100...

SECTION 1

Why Do We Count?

People have been counting for a very, very long time! Long ago, people needed to know how many sheep they had. They needed to know how many fish they caught. Counting helped them keep track of things.

At first, people used their fingers to count. They could count to ten on their fingers! But what happens when you have more than ten things? People had to come up with new ideas.

Long Ago

Counting on Fingers

People used their ten fingers to count things like food and animals.

Very Old

Marks on Bones

People scratched lines on bones and sticks to keep track of big numbers.

Old Times

Number Words

People made up words for numbers like one, two, three, all the way up to one hundred and more!

Later

Written Numbers

People started writing numbers like 1, 2, 3 so everyone could understand them.

Today, you will learn to count all the way to 100! You will count by ones and by tens. This is a super important skill that will help you in math and in everyday life.

SECTION 2

Big Ideas About Counting

Before we start counting to 100, let's learn some big ideas. These ideas will make counting easier and more fun!

Counting by Ones

When you count by ones, you say every number in order: 1, 2, 3, 4, 5, and so on. Each number is one more than the last.

Counting by Tens

When you count by tens, you skip numbers and say only the tens: 10, 20, 30, 40, and so on. This is a fast way to count!

Number Order

Numbers always go in the same order. After 1 comes 2. After 9 comes 10. After 99 comes 100. The order never changes!

Patterns Help Us

Numbers make patterns. After every 9 comes a new ten. The pattern 1, 2, 3, 4, 5, 6, 7, 8, 9 repeats in every row of ten!

✦ KEY TAKEAWAY

Think of counting like climbing stairs. When you count by ones, you go up one step at a time. When you count by tens, it is like jumping up ten stairs at once! Both ways get you to the top, but counting by tens is much faster.

SECTION 3

The Hundred Chart

A hundred chart shows all the numbers from 1 to 100 in a big grid. It has 10 rows and 10 columns. Each row has 10 numbers. Look at the chart below to see all the numbers!

The hundred chart shows numbers 1 to 100. The yellow boxes show the tens: 10, 20, 30, 40, 50, 60, 70, 80, 90. The green box at the end is 100! You read across each row from left to right.

Look at the chart above. Each row has exactly 10 numbers. The first row goes from 1 to 10. The second row goes from 11 to 20. Do you see the pattern? Every row ends with a tens number — 10, 20, 30, 40, 50, 60, 70, 80, 90, 100!

SECTION 4

How Counting Works

When you count by ones, you add one more each time. When you count by tens, you add ten more each time. Let's look at how this works!

Counting by Ones

COUNTING BY ONES

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 … all the way to 100

Each number is one more than the number before it. For example, 5 is one more than 4. The number 56 is one more than 55.

Counting by Tens

COUNTING BY TENS

10, 20, 30, 40, 50, 60, 70, 80, 90, 100

Each number is ten more than the number before it. For example, 30 is ten more than 20. When you count by tens, you only say 10 numbers to get to 100!

⭐ Fun Fact!

When you count by ones from 1 to 100, you say 100 numbers. But when you count by tens, you only say 10 numbers to reach 100. That is much faster!

Here is a helpful trick. All the tens numbers end in zero. Look: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. Every single one ends with a 0. This makes them easy to spot!

SECTION 5

Patterns in Numbers

Numbers follow patterns. When you learn the pattern, counting becomes easier. Let's look at how numbers between 1 and 100 are organized.

The top number line shows counting by tens from 10 to 100. Below it, the twenties row shows the pattern inside each group of ten. The ones digit goes 1, 2, 3, 4, 5, 6, 7, 8, 9 — the same pattern repeats in every group!

The first five groups of ten numbers

Group	Numbers	Ends With
Ones	1, 2, 3, 4, 5, 6, 7, 8, 9, 10	10
Teens	11, 12, 13, 14, 15, 16, 17, 18, 19, 20	20
Twenties	21, 22, 23, 24, 25, 26, 27, 28, 29, 30	30
Thirties	31, 32, 33, 34, 35, 36, 37, 38, 39, 40	40
Forties	41, 42, 43, 44, 45, 46, 47, 48, 49, 50	50

This table shows the first five groups. The pattern keeps going with the fifties (51–60), sixties (61–70), seventies (71–80), eighties (81–90), and nineties (91–100). Every group has exactly 10 numbers!

SECTION 6

Let's Practice Together

Let's try counting together! We will do two examples — one counting by ones and one counting by tens.

Example 1: Count by Ones from 24 to 33

Step 1 — Start at 24We are in the twenties. The ones digit is 4. We say: 24.

Step 2 — Keep counting the twentiesAdd one more each time: 25, 26, 27, 28, 29. The ones digit goes 5, 6, 7, 8, 9.

Step 3 — Cross into the thirtiesAfter 29, the next number is 30! We move to a new group of ten.

29 → 30

Step 4 — Continue in the thirtiesNow keep going: 31, 32, 33. We have counted from 24 all the way to 33!

24, 25, 26, 27, 28, 29, 30, 31, 32, 33

Example 2: Count by Tens from 10 to 100

Step 1 — Start at 10Our first number is 10. Think of 10 as one group of ten.

Step 2 — Jump by ten each timeSay: 10, 20, 30, 40, 50. We are halfway there! Each number is ten more than the last.

Step 3 — Keep going!Continue: 60, 70, 80, 90. Almost at the end!

Step 4 — Finish at 100The last number is 100! We said only 10 numbers and reached one hundred.

10, 20, 30, 40, 50, 60, 70, 80, 90, 100

SECTION 7

Counting by Ones vs. Counting by Tens

Both ways of counting are important! Let's compare counting by ones and counting by tens to see when each way is helpful.

Feature	Counting by Ones	Counting by Tens
How many numbers do you say?	100 numbers	Only 10 numbers
Speed	Slow — takes a while	Fast — done quickly!
What you skip	Nothing — every number	You skip 9 numbers each time
Best for	Counting small groups one by one	Counting big groups of ten
Example	Counting 7 crayons	Counting 50 pennies in stacks of 10

✦ KEY TAKEAWAY

Think of it like walking to school versus riding a bike. Counting by ones is like walking — you see every house along the way. Counting by tens is like riding a bike — you go much faster but you pass some houses without stopping. Both get you to school!

SECTION 8

Getting Ready for Bigger Numbers

Once you can count to 100 by ones and tens, you are ready for even more! Here is what you will learn next as you grow as a math star.

What You Know Now	What Comes Next
Count to 100 by ones	Count to 120 and beyond!
Count to 100 by tens	Count by twos and fives (skip counting)
Spot the pattern 1–9 in each group	Understand tens and ones (place value)
Say numbers in order	Count objects to tell how many (cardinality)

Learning to count to 100 is one of the most important things you do in kindergarten. It is the foundation for all the math you will do in first grade and second grade and beyond. Great job learning this skill!

🌟 Keep Practicing!

Try counting to 100 every day! You can count while climbing stairs, eating snacks, or lining up blocks. The more you practice, the easier it gets. Soon you will be counting to 100 super fast!

SECTION 9

Practice Problems

Now it is your turn! Try these problems to show what you have learned about counting to 100 by ones and by tens.

PROBLEM 1 — CONCEPTUAL

When you count by tens, what number comes after 50?

PROBLEM 2 — BASIC CALCULATION

Fill in the missing numbers: 36, 37, 38, ___, ___, 41.

PROBLEM 3 — INTERMEDIATE

Count by tens starting at 10. How many numbers do you say before you reach 100? (Count 100 too!)

PROBLEM 4 — APPLIED

You have 7 bags of apples. Each bag has 10 apples. You count the apples by tens. What numbers do you say?

PROBLEM 5 — CRITICAL THINKING

Sam counted by tens and said: 10, 20, 30, 50, 60. Did Sam make a mistake? If yes, what did Sam forget?

SUMMARY

What We Learned

In this lesson, you learned two ways to count to 100. Counting by ones means saying every number in order — 1, 2, 3, 4, 5 and so on — all the way to 100. Each number is one more than the last. Counting by tens means jumping by ten each time — 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. Each number is ten more than the last, and every tens number ends in zero.

You also learned about patterns in numbers. The ones digit repeats 1, 2, 3, 4, 5, 6, 7, 8, 9 in every group of ten. A hundred chart is a great tool that shows all 100 numbers in 10 rows. Keep practicing counting every day — you are doing an amazing job!