This page has been robot translated, sorry for typos if any. Original content here.

# Tricks to master Math

We were simply not taught in school as it should, because mathematical tricks with which any calculations become elementary are easier to remember.

Multiplication of large numbers in the mind, How to learn the multiplication table by 9, Butterfly method for adding and subtracting fractions, Multiplying numbers by 11 (using the example of the number 32), How to remember Pi, How to find the percentage of the number, How to find the fraction of the whole Converting Faryngate degrees to Celsius, Fast squaring, Multiply by 5, Multiply by 11, Multiply by 4, Complex multiplication, Divide by 5, Subtract from 1000

## Quick squaring

This technique will help to quickly square a two-digit number that ends with 5. Multiply the first digit by itself + 1, and add 25. at the end. That's all!

## Multiplication by 5

Divide the number by 2. If the result is an integer, add a 0 at the end. If not, ignore the comma and add 5 at the end.

## Tip counting

If you need to leave a 15% tip, there is an easy way to determine how much it is. Calculate 10% (divide the number by 10), and then add the resulting number to its half and get the answer.

## Complex multiplication

If you need to multiply large numbers, and one of them is even, you can simply regroup them to get the answer.

## Division by 5

In fact, it’s very easy to divide large numbers by 5. All you need is to simply multiply by 2 and move the comma.

## Subtract from 1000

To perform a subtraction from 1000, you can use this simple rule: subtract from 9 all the digits except the last, and subtract the last digit from 10.