# Mind Mathematics: Trick Set #3

Now that we have completed the basic mathematical tricks, it is time to get into something more sophisticated. In this trick set, you will be learning some advanced mathematical tricks, such as percentage tricks, etc. So, tighten up your seat belts, and enjoy the mathematical ride.

## Percentage Trick

We often get confused when we are asked to find the particular percentage of a number. Well, you will undoubtedly no longer need to worry about it after learning this trick.

Suppose we have to find 5% of 366, what do we do?

We just need to take 366 and move its decimal point by one place so that it becomes 36.6.

After that, we divide 36.6 by 2 and get 18.3% which, my friend, is also 5% of 366.

So far you’ve learned how to multiply by 5 and 9, let’s learn about multiplication by 10 and 11 now.

### Multiplication by 10

If you want to multiply any number by 10, just don’t do it. Just add 0 at the end of that number, you will get the answer.

For example, 15 multiplied by 10 = 150.

### Multiplication by 11

The multiplication trick for 10 was an easy one, let’s do it for 11 now.

Let’s take the number 15; to multiply it by 11, simply place the sum of its two digits between the two digits like this:

For 15 * 11, 1 (1 + 5) 5 = 165, which is your answer.

We hope you find our mathematical tricks fun and easy to learn, and we are continuously working to keep you updated with more mathematical tricks, in the next trick sets, which you can easily visit from this portal.

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