What Are the Multiples of 9? Chart, Methods, and Easy Tricks

Do you know why multiples of 9 always seem a little magical?
Why do their digits often add up to 9, 18, or 27? And why do teachers love using 9 to teach math patterns?

Wukong Edu will explore the multiples of 9 together! In this guide, you’ll learn what they are, see clear lists and tables, discover easy tricks kids love, and understand how multiples of 9 show up in real life. This article is perfect for students, parents, and beginners who want math explained simply.

Definition of Multiples of 9

A multiple of 9 is any number you get when you multiply 9 by a whole number.

In other words:

• 9 × 1 = 9
• 9 × 2 = 18
• 9 × 3 = 27

Each result is a multiple of 9.

Simple Rule

If a number can be written as 9 × a whole number, then it is a multiple of 9.

Examples:

• 36 = 9 × 4 ✅
• 90 = 9 × 10 ✅
• 25 ❌ (not a multiple of 9)

Chart of the First 20 Multiples of 9

Below is a clear table showing the first 20 multiples of 9. This is great for memorization and quick reference.Have kids read this table aloud.And it helps with number rhythm and memory.

What Are the Multiples of 9 Up to 150?

Here are the multiples of 9 up to 150 👇

9, 18, 27, 36, 45,
54, 63, 72, 81, 90,
99, 108, 117, 126, 135, 144

✅ These are all the numbers you get by multiplying 9 × 1 through 9 × 16

❌ 9 × 17 = 153, which is greater than 150, so it’s not included.

How Many Multiples of 9 Are in 100?

To find how many multiples of 9 are in 100, divide 100 by 9 and keep only the whole number:

100 ÷ 9 = 11.11…

So there are 11 multiples of 9 in 100.

The multiples of 9 up to 100 are:

9, 18, 27, 36, 45,
54, 63, 72, 81, 90, 99

✅ Answer: 11 multiples of 9
❌ The next one, 108, is greater than 100.

How to Explain Multiples of 9 Simply to a Child?

This is where multiples of 9 become really fun. They follow patterns that make them easy to spot.

1. Digit Sum Trick (Most Famous!)

Add the digits of a number.

• If the digits add up to 9 or a multiple of 9, the number is a multiple of 9.

Examples:

• 45 → 4 + 5 = 9 ✅
• 72 → 7 + 2 = 9 ✅
• 162 → 1 + 6 + 2 = 9 ✅

If the sum is not 9, 18, 27, etc., then it’s not a multiple of 9.

This trick is part of the divisibility rule for 9, which you’ll see again later.

2. Finger Trick for 9 Times Table

Kids love this one!

1. Hold up both hands (10 fingers).
2. To find 9 × 4, bend down your 4th finger from the left.
3. Count fingers:

• Fingers on the left = tens
• Fingers on the right = ones

You’ll get 36!

This trick works for 9 × 1 through 9 × 10 and helps visual learners a lot.

3. Number Pattern in the Ones and Tens

Look at the multiples of 9:

• 09
• 18
• 27
• 36
• 45
• 54
• 63
• 72
• 81
• 90

Notice:

• The tens digit goes up by 1
• The ones digit goes down by 1

This beautiful pattern is one reason teachers call multiples of 9 “math magic.”

Common Multiples of 9 and 10~27 with LCM

Let’s explore what common multiples are and how to find the Least Common Multiple (LCM) for two numbers. We’ll look at two pairs: 9 and 10, and 9 and 27.

What Are Common Multiples?

Common multiples are numbers that are multiples of two or more given numbers. For example, a number that is a multiple of both 9 and 10 is a common multiple of 9 and 10.

The Least Common Multiple (LCM) is the smallest positive number that is a multiple of both numbers. It’s a key concept for adding fractions and solving many math problems.

Common Multiples of 9 and number N(example:10)

Step 1: List Some Multiples

• Multiples of 9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 108, …
• Multiples of 10: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, …

Step 2: Identify Common Multiples

Looking at the lists, the first number that appears in both is 90. The next one is 180 (since 9×20=180 and 10×18=180).

A few common multiples of 9 and 10 are: 90, 180, 270, 360, 450, …

Step 3: Find the LCM

The smallest common multiple is 90. Therefore:
LCM(9, 10) = 90.

Quick Fact: Since 9 and 10 share no common factors (they are relatively prime), their LCM is simply their product: 9 × 10 = 90. All common multiples are multiples of 90.

Examples and Real-Life Applications

You might wonder: Where do we actually use multiples of 9?

Example 1: Money

If one toy costs $9:

• 3 toys cost 9 × 3 = 27 dollars
• 5 toys cost 9 × 5 = 45 dollars

Those totals are multiples of 9.

Example 2: Time and Calendars

• 9 minutes, 18 minutes, 27 minutes… all multiples of 9
• Many puzzles and math games use multiples of 9 to test number sense

Example 3: Classroom Math

Teachers often use multiples of 9 to:

• Teach patterns
• Introduce division
• Compare with other concepts like multiples of 3 or multiples of 6
  (You can explore those topics next for deeper understanding.)

Related Concepts: Divisibility Rule for 9

The divisibility rule for 9 helps you check large numbers quickly.

The Core Rule

A number is divisible by 9 if and only if the sum of its digits is also divisible by 9.

How and Why It Works

In our number system, every place value (ones, tens, hundreds) is a power of 10. When you divide any power of 10 (like 10, 100, or 1000) by 9, the remainder is always 1.

This means a number like 567 is really:
(5 x 100) + (6 x 10) + (7 x 1)
When divided by 9, this is the same as:
(5 x 1) + (6 x 1) + (7 x 1) = 5 + 6 + 7
…which is just the sum of its digits (18).

Therefore, the original number (567) and the sum of its digits (18) will have the same remainder when divided by 9. If the digit sum is divisible by 9 (remainder 0), then the original number is also divisible by 9.

Examples

• Is 189 divisible by 9?
  Digit sum: 1 + 8 + 9 = 18.
  Since 18 ÷ 9 = 2 (no remainder), 189 is divisible by 9. (189 ÷ 9 = 21)
• Is 999 divisible by 9?
  Digit sum: 9 + 9 + 9 = 27.
  Since 27 ÷ 9 = 3, 999 is divisible by 9. (999 ÷ 9 = 111)
• Is 1,234 divisible by 9?
  Digit sum: 1 + 2 + 3 + 4 = 10.
  10 ÷ 9 = 1 with a remainder of 1. Therefore, 1,234 is NOT divisible by 9.

Related Concepts

• Divisibility Rule for 3: A number is divisible by 3 if the sum of its digits is divisible by 3. (This is related but a weaker condition than the rule for 9).
• Digit Sum: The foundation of this rule. You can repeat the digit sum process (e.g., for 99, 9+9=18, then 1+8=9) until you get a single digit.
• Casting Out Nines: A historical technique for checking arithmetic calculations, based on this same principle.
• Factors and Multiples: If a number ‘N’ is divisible by 9, then 9 is a factor of ‘N’, and ‘N’ is a multiple of 9.

Multiplication Tables

Multiplication Tables From 1-24

This collection of multiplication resources is designed to support mastery of Common Core State Standards for Operations and Algebraic Thinking. Specifically, it aligns with CCSS.MATH.CONTENT.3.OA.C.7, which requires students to fluently multiply and divide within 100, and 4.OA.B.4, focusing on factors and multiples. By exploring these tables, learners develop the algebraic foundation necessary for mental math fluency and higher-level problem solving.

Final Thoughts

Remember, multiples of 9 are everywhere in math—and they follow some of the coolest patterns you’ll ever see.

Key Takeaways:

• Multiples of 9 come from 9 × whole numbers
• Their digits often add up to 9 or 18
• Easy tricks make them fun and simple to learn
• They help build strong number sense for future math topics

Try this next:Look around and see how many multiples of 9 you can spot today. Practice makes patterns stick!How many multiples of nine are there? When doing arithmetic, how can one avoid confusion? Remember to read this article from Wukong Math. The courses and teachers here will help you solve this problem.

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James | WuKong Math Teacher

Graduated from Columbia University in the United States and has rich practical experience in mathematics competitions’ teaching, including Math Kangaroo, AMC… He teaches students the ways to flexible thinking and quick thinking in sloving math questions, and he is good at inspiring and guiding students to think about mathematical problems and find solutions.