## Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community!

### Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial###### Tomasz Grodzki

8,130 Points# Why Math.floor ( Math.random() * 6 ) + 1; works good but Math.floor ( Math.random() * 6 ) + 4; doesn't?

In this lesson we've got such a code: var number = Math.floor ( Math.random() * 6 ) + 1; - and this code draws numbers from 1 to 6... okay, everything's clear. But why this code: var number = Math.floor ( Math.random() * 6 ) + 4; doesn't draws numbers from 4 to 6... It gives me numbers like 8, 7, 9 etc...

## 4 Answers

###### Dmitry Polyakov

4,989 PointsTo get a numbers range starting and ending with some certain numbers that you want you need to use Math.floor(Math.random() * (max - min)) + min

max - is not included

For example:

Math.floor(Math.random() * (11 - 5)) + 5

You'll get numbers from 5 to 10 (11 won't be generated)

###### Dmitry Polyakov

4,989 PointsIt should work. I just checked it. It generates numbers from 4 till 9

###### Tomasz Grodzki

8,130 PointsWell... it still gives me numbers from 4 to 9. Im using exactly this code: var number = Math.floor ( Math.random() * 6 ) + 4; document.write ( number );

And I know the solution. I know that if I'll write: var number = Math.floor ( Math.random() * ( 6 - 4 + 1 ) ) + 4; document.write ( number ); then I'll get numbers from 4 to 6... But I don't understand why this first solution doesn't work well.

###### Dmitry Polyakov

4,989 PointsWhat result do you want to get?

###### Tomasz Grodzki

8,130 PointsIf code Math.floor ( Math.random() * 6 ) + 1 gives me number from 1 to 6... then why code Math.floor ( Math.random() * 6 ) + 4 doesnt give me a number from 4 to 6?

## Tomasz Grodzki

8,130 Points## Tomasz Grodzki

8,130 PointsNow I understand this formula. Math.floor(Math.random() * (b)) + a; Where "a" is the lowest number, and "b" is how many numbers program takes into consideration after "a". I simply thought that a is the lowest number and b is the highest number...