Recognizing rational and irrational numbers (examples) | Algebra I | Khan Academy

Given a bunch of numbers, learn how to tell which are rational and which are irrational.

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Algebra I on Khan Academy: Algebra is the language through which we describe patterns. Think of it as a shorthand, of sorts. As opposed to having to do something over and over again, algebra gives you a simple way to express that repetitive process. It's also seen as a "gatekeeper" subject. Once you achieve an understanding of algebra, the higher-level math subjects become accessible to you. Without it, it's impossible to move forward. It's used by people with lots of different jobs, like carpentry, engineering, and fashion design. In these tutorials, we'll cover a lot of ground. Some of the topics include linear equations, linear inequalities, linear functions, systems of equations, factoring expressions, quadratic expressions, exponents, functions, and ratios.

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[mnunez]

I knew a friend who got a tattoo of pi on her shoulder arm; man, that's some irrational thinking right there.

[CraicyPlays]

How come youtube teaches me more than my actual teachers

[harderhscmaths]

Bowen is correct, for example sqrt(2)*sqrt(8)=4 both are irrational.

[harderhscmaths]

Sal's video is absolutely correct so I am not sure what Bowen is referring to.

[pathwayc]

how to prove that 7.777... is rational?

[chaosopher]

Irrational numbers are those you cannot reason with.

if you multiple irrational by irration you could have a real number, so

[ded]

precisely the explanation I was looking for. Thank you!

[BassmrDK]

Nice! I always thought 1/3 was considered irrational…

[bowenkerins]

It's not valid to say you could multiply or divide an irrational number by "any other number" to get an irrational number. The other number needs to be rational and nonzero to guarantee that the product or quotient is irrational.

[andrijorellmetica]

sana all matalino awitt
joke!
sasusunod ulit salamat
dhl ikw ang bumuo ng math ko! joke
salamat tlaga
tnx to your teaching uss 😁💗💯😎🤔

[sqweebel]

Shouldn't being divisible by one not count as criteria for being rational, since you can divide irrationals numbers by 1?

[vivianlam]

We are learning this in math, thanks!

[sdeb]

But Pi can be written as 22/7 ... you said 17/2 is real...then 22/7 should also be real

[loganthomas]

OMG I needed this. Best 2 minute math video ever

[epicgamer_yt]

Can't you represent pi as 22/7? So that is a ratio of 2 integers which makes it rational?

[aneesurrehman]

0.31311311131111.... Is a rational or irrational plzz give the answer

[kaypromena]

why is the SR of 8 ( equaling 4) over 2 irrational, but 17 over 2 is rational?

[IanIsTheCoolest]

But pi over 1 is not a ratio of two *integers*.

[swatimandal]

how is pie not a rational number? pie=22/7 =22:7 (ratio)