9 Math Tricks for Kids & Adults [+Examples & Answers]

Math tricks train your brain and develop your IQ by teaching you to solve problems in original ways and boosting your mental agility and logical-mathematical intelligence.

In addition, they are an excellent way to make math more digestible for children, who tend to find the subject too challenging and boring. Some math tricks can transform complex calculations into a fun game that most kids are eager to participate in.

Whether you’re a parent, teacher, or simply someone who likes math, our tried-and-true math tricks will equip you with the necessary techniques to tackle large numbers and confidently perform difficult calculations.

So, let’s dive in.

9 Mind-Blowing Math Tricks

Kids drawing on the ground and learning math tricks

The following math tricks with answers and examples will help you do most calculations in your head, relying only on your brain power. Thanks to that, your confidence in math will grow, and you’ll impress both your friends and teachers.

#1. Subtracting from 1,000

Instead of reaching for your calculator when subtracting a large number from a thousand, try the following math trick:

Step 1: Subtract the first and second digits from number 9. For example, if your number is 648, you need to subtract both 6 and 4 from 9, getting 3 and 5, respectively.

Step 2: Subtract the final digit from number 10. In our example, the result will be 2.

Step 3: Put the results of each subtraction together to get the final result, which, in our case, would be 352.

This method also works for subtracting two-digit numbers from 1,000, but you must remember to place a 9 before the first digit.

After all, using this method to subtract 64 from 1,000, you’d get 36, which obviously isn’t right. But if you place a 9 in front of that result, the solution becomes 936—the correct answer.

#2. Multiplying Large Numbers

When multiplying large numbers, the best approach is to separate one of the numbers into two more manageable components, multiply the other number with both, and then add the results together.

Let’s see how we’d solve 25 x 14 using this multiplication math trick.

Step 1: First, separate 14 into 10 and 4.

Step 2: Multiply 25 by both numbers from Step 1. That way, you will get 25 x 10 = 250 and 25 x 4 = 100.

Step 3: Add the two results from Step 2 together to get the final solution: 250 + 100 = 350.

So, 25 x 14 = 350.

#3. Multiplying Numbers That End in Zero

If the numbers you’re multiplying end in zero, it doesn’t matter how large they are—they will be easy to multiply off the top of your head.

For example, let’s say you’re multiplying 6,000 by 400. Here is how you should approach the task:

Step 1: Multiply the digits that aren’t zero. In this case, that’s 6 x 4, which equals 24.

Step 2: Put all the zeros together and place them behind the result you got in Step 1. In our example, there are three zeros in 6,000 and two in 400, which give us five combined.

So, 6,000 x 400 = 2,400,000.

#4. Division Tricks

Division math tricks

Here are a few simple math tricks to help you determine whether a number can be evenly divided by the first ten numbers:

1

All numbers are divisible by 1.

2

The number ends with 0, 2, 4, 6, or 8.

Example: 44, 372, 888

3

The sum of all digits is divisible by 3.

Example: 66, 651, 1,071

4

The last two digits are divisible by 4.

Example: 744, 3616, 10,224

5

The number ends in 0 or 5.

Example: 60, 1,255

6

The number is even, and the sum of its digits is divisible by 3.

Example: 72, 132, 1,110

7

Take the last digit of the number, multiply it by 2, and then subtract the result from the remainder of the number. If the result is divisible by 7, the original number is too.

Example: 441 (2 x 1 = 2, 44 – 2 = 42, which is divisible by 7)

8

The last three digits are 000, or divisible by 8.

Example: 1000, 2,416

9

The sum of all digits is divisible by 9.

Example: 135, 4,239

10

The number ends in 0.

Example: 270, 3,650

#5. The 11 Rule

The 11 rule allows you to quickly multiply two-digit numbers by 11. Here’s how it works, using 11 x 43 as an example:

Step 1: Take the number you’re multiplying and put a space between the two digits. Our example will look something like this: 4_3.

Step 2: Add the two digits together and put the result in the center as follows:

4_(4+3)_3 = 473

In other words, 11 x 43 = 473.

But what happens if you have 11 x 49, where the result of the addition in Step 2 is a two-digit number? You can use the same method, but insert only the second digit in the center and add 1 to the first digit of the result in Step 1.

Here is an example:

11 x 49

4_(4+9)_9

4_(13)_9

(4+1)_3_9

The result is 539.

#6. Adding Large Numbers

Most people need to use a calculator to add large numbers, such as 568 and 376. However, with this simple math trick for fast calculation, you won’t struggle with addition again.

Here is a step-by-step explanation:

Step 1: Round both numbers to a higher number divisible by 10. In our case, 568 becomes 570, and 376 becomes 380.

Step 2: Now that you have more manageable numbers, add them together. In our example, the result will be 570 + 380 = 950.

Step 3: Think back to how much you added to each number to round it up. To get 570 and 380, we added 2 to 568 and 4 to 376.

Step 4: Add the numbers from Step 3 together to determine how much you should subtract from the result in Step 2 to get the actual result. So, 2 + 4 = 6.

Step 5: Now, subtract 6 from 950 to get the answer to the original addition.

The final solution is 944.

#7. Using Fingers to Multiply by 9

Did you know that you have a built-in 9-multiplication table in your fingers? Although it only helps you multiply 9 by the first ten numbers, it’s still a useful tool and a fun math trick.

Here is how to use it:

Step 1: Raise both hands with fingers and thumbs extended and palms facing away from your body.

Step 2: Assign each finger a number from 1 to 10 in order, starting from left to right. When you’re done, the pinky of your left hand should be number 1, and the pinky of your right hand should be number 10.

Step 3: Decide which number to multiply by 9 and fold the corresponding finger. For example, if you’re calculating 9 x 4, fold the index finger of the left hand.

Step 4: Count how many fingers are raised on the left of the folded finger. In our case, there will be 3, which is the first digit of the solution.

Step 5: Count how many fingers are raised on the right of the folded finger. In our example, that’s 6, the second digit of the solution.

Step 6: Combine the first and second digits, 3 and 6, and you’ll get the answer: 36.

#8. Memorizing Pi

The value of Pi

Most people know the first three digits of Pi (3.14) but struggle to remember anything beyond that. However, there’s an easy trick to help you memorize seven digits and impress all your friends.

All you have to do is count the letters in each word of the following sentence:

“How I wish I could calculate Pi.”

The result is: how (3) I (1) wish (4) I (1) could (5) calculate (9) Pi (2).

When you put all the numbers together, you get 3.141592—the first seven digits of Pi.

#9. Squaring a Two-Digit Number That Ends in 5

If someone asked you to square number 65, you likely wouldn’t be able to answer off the top of your head. Instead, you’d reach for a piece of paper to solve the problem.

But the following math trick will help you perform this seemingly complex calculation within seconds, making you look like a math genius.

Here is what you have to do:

Step 1: Multiply the first digit of the number by itself plus 1. In our example, that’s 6 x (6+1), which results in 42.

Step 2: Put 25 at the end of the number you got in Step 1.

And that’s it—65 squared is 4,225. Try it on a few other two-digit numbers ending in 5, and you’ll see this simple trick works every time!

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Key Takeaways

Whether your goal is to get a good grade on a test, develop your IQ potential, or refresh your math knowledge, math tricks are an excellent tool to help. There’s no better way to exercise your mind than to review each one a few times until you memorize the steps.

With enough mental exercise, these tricks will come to you automatically, making you come across as a real math expert!