Read the Tens Digit in 10–90 - 1st Grade Math

SECTION 1

Why We Count in Groups of Ten

Long ago, people needed to count many things. They counted sheep, fruits, and tools. Using their ten fingers helped them keep track! When they ran out of fingers, they made groups of ten. This is why we use numbers like 10, 20, 30, and so on.

Ancient • Finger Counting

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

Early • Groups of Ten

When people had more than ten things, they made groups of ten.

Later • Two-Digit Numbers

People learned to write numbers with two parts: tens and ones.

Today • Reading Numbers

We can quickly see how many groups of ten are in any number!

Today, we still use this idea of counting in tens. When we see numbers like 23 or 47, we can tell exactly how many groups of ten they have. This helps us understand big numbers better!

SECTION 2

What Are Tens and Ones?

Every number from 10 to 90 has two important parts. The tens digit tells us how many groups of ten we have. The ones digit tells us how many single things are left over.

Tens Place

The first digit in a two-digit number. It shows how many groups of ten we have.

Ones Place

The second digit in a two-digit number. It shows how many single things are left.

Reading Left to Right

We always read the tens digit first, then the ones digit, just like reading words!

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KEY TAKEAWAY

Think of numbers like toy boxes! The tens digit tells you how many big boxes you have, each holding exactly 10 toys. The ones digit tells you how many loose toys are sitting outside the boxes!

SECTION 3

See the Tens and Ones

The number 45 has a tens digit of 4 (shown as 4 groups of 10 blue squares) and a ones digit of 5 (shown as 5 pink circles). Look at the other examples to practice reading tens digits!

Look at the picture above! The tens digit is always the first number you see. In 45, the tens digit is 4. This means we have 4 groups of ten things. The ones digit is 5, which means 5 things are left by themselves.

SECTION 4

How Place Value Works

Every spot in a number has a special job. We call these spots place value. The place tells us how much each digit is really worth!

PLACE VALUE RULE

Two-digit number = (tens digit × 10) + (ones digit × 1)

The tens digit gets multiplied by 10 because it represents groups of ten. The ones digit gets multiplied by 1 because it represents single items.

EXAMPLE WITH 73

73 = (7 × 10) + (3 × 1) = 70 + 3

The 7 in the tens place is worth 70, and the 3 in the ones place is worth 3. Together they make 73!

When we want to find the tens digit in any number from 10 to 90, we just look at the first digit! That first digit tells us exactly how many groups of ten we have.

SECTION 5

Tens Digit Patterns

Numbers are organized in patterns by their tens digit. All numbers from 10-19 have a tens digit of 1, all numbers from 20-29 have a tens digit of 2, and so on. The special numbers ending in 0 have only tens and no ones!

Look at the cool patterns! All numbers that start with 2 have 2 tens. All numbers that start with 5 have 5 tens. The first digit you see always tells you how many groups of ten are hiding inside the number!

SECTION 6

Finding the Tens Digit Step by Step

Let's practice finding the tens digit in the number 84. We'll go through it step by step so you can see exactly how to do it!

Finding the Tens Digit in 84

1
Step 1 — Look at the Number

We have the number 84. We can see there are two digits: 8 and 4. We need to figure out which one is the tens digit.

Number: 84
2
Step 2 — Find the First Digit

When we read from left to right, the first digit we see is 8. This first digit is always in the tens place.

First digit: 8
3
Step 3 — Name the Tens Digit

The tens digit in 84 is 8. This means we have 8 groups of ten, plus 4 ones left over.

Tens digit: 8
4
Step 4 — Check Our Answer

Let's make sure! 8 tens = 80, and 4 ones = 4. Together: 80 + 4 = 84. Perfect!

Check: 8 × 10 + 4 × 1 = 80 + 4 = 84 ✓

SECTION 7

Easy Ways to Remember

Helpful Trick	Example	Why It Works
Look Left First!	In 56, look left and see 5	We read numbers from left to right, just like words
Cover the Last Digit	Cover the 3 in 73, see 7	The tens digit is what's left when you hide the ones
Count by Tens	For 42: 10, 20, 30, 40... that's 4 tens!	Counting by tens shows you how many groups you have

Three easy tricks to help you find the tens digit quickly

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KEY TAKEAWAY

Think of reading tens digits like finding the captain of a team! The tens digit is the leader that stands in front. In the number 67, the 6 is the captain leading 6 teams of 10, while the 7 is like extra players waiting on the side!

SECTION 8

Moving to Bigger Numbers

Once you know how to find the tens digit in numbers like 10-90, you're ready for even bigger numbers! Numbers can have hundreds, thousands, and more places too!

What You Know Now	What's Coming Next
Reading tens digit in 2-digit numbers (10-99)	Reading hundreds digit in 3-digit numbers (100-999)
Understanding 'tens place' and 'ones place'	Learning 'hundreds place,' 'thousands place,' and more!
Numbers like 25, 47, 83	Numbers like 125, 347, 1,283

The great news is that the same left-to-right reading trick works for all numbers! You'll always read digits from left to right to figure out what each place is worth.

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

Look at the number 36. Which digit tells you how many groups of ten you have?

Show answer

The digit 3 tells you how many groups of ten you have. In the number 36, the 3 is in the tens place, which means there are 3 groups of ten. The 6 is in the ones place, which means there are 6 single items left over. So 36 = 3 tens + 6 ones = 30 + 6.

Question 2: BASIC CALCULATION

What is the tens digit in the number 52?

Show answer

The tens digit in 52 is 5. We know this because when we read from left to right, the first digit is 5, and the first digit is always in the tens place. This means 52 has 5 groups of ten plus 2 ones, which gives us 50 + 2 = 52.

Question 3: INTERMEDIATE

Find the tens digit in each of these numbers: 18, 67, and 90. Explain why 90 is special.

Show answer

The tens digits are: 18 has tens digit 1, 67 has tens digit 6, and 90 has tens digit 9. The number 90 is special because it has 0 in the ones place, which means it has exactly 9 groups of ten with no extra ones left over. It's like having 9 complete boxes with nothing left outside the boxes!

Question 4: APPLIED

Maria has 45 stickers. She wants to put them in groups of 10. How many complete groups of 10 can she make? Which digit in 45 tells you this answer?

Show answer

Maria can make 4 complete groups of 10 stickers. The tens digit 4 in the number 45 tells us this answer directly! Since 45 = 4 tens + 5 ones, she will have 4 groups of 10 stickers each, with 5 stickers left over that don't make a complete group. The tens digit always shows how many complete groups of ten you can make.

Question 5: CRITICAL THINKING

Think of a number between 10 and 90 where the tens digit is the same as the ones digit. Give three examples and explain what makes these numbers special.

Show answer

Three examples are 11, 22, 33, 44, 55, 66, 77, 88. These numbers are special because both digits are the same! In 33, both the tens digit and ones digit are 3, which means 3 tens + 3 ones = 30 + 3 = 33. These are called 'double digit' numbers, and they create a pattern where the number looks the same in both places. They're easy to remember because they use the same digit twice!

SUMMARY

Reading the Tens Digit in 10–90

Summary

Reading the tens digit is easy once you know the trick! The first digit you see when reading from left to right is always the tens digit. This digit tells you how many groups of ten are hiding inside the number. In 47, the tens digit is 4, which means 4 groups of ten. In 83, the tens digit is 8, which means 8 groups of ten.

Remember that every two-digit number has a tens place and an ones place. The tens digit shows complete groups of ten, while the ones digit shows leftover single items. This pattern helps us understand how numbers work and makes counting easier. Now you can read the tens digit in any number from 10 to 90!