If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Lesson 4: Understanding multiplying and dividing fractions

# Expressions with rational numbers

Learn to compare expressions with positive and negative fractions. Created by Sal Khan.

## Want to join the conversation?

• I know Sal is working through solving each answer to see if it equals -2/3, however with the initial question being that, shouldn't we eliminate examples one and three right away as being positive regardless of their values?
• Yes, if this were an exam question, then that would be a very sensible shortcut. Here, I think Sal was more interested in showing examples of working with rational numbers rather than simply getting the answer.
• what is a rational number?
• A rational number is a number that can be written as a fraction, for example, 2/1, or 4/5. It doesn't matter if the fraction can be turned into a whole number or not. In comparison, an irrational number is one that is a recurring decimal with no repetition, eg pie, or 5.624319678.
• at Sal said that -1+ -3= -4, but we learned that a negative + a negative = positive, not negative.
• he said that negative times negative = positive but a negative added to another negative is still a negative
• is a fraction rational or irrational?
• Rational. A rational number is a number that can be represented by the fraction of two integers. So, fractions are naturally rational. Hope this is helpful! :-)
• If we have one fraction with a negative numerator plus a fraction with a negative denominator, do we simply pretend that both fractions have negative numerators? For example, if our equation is -5/3 + 2/-3, should our answer be -7/3?
• I personally tend to think about the negative sign being before the fraction, like -(5/3) -(2/3). I think having it in the numerator is also acceptable, but it probably shouldn't be in the denominator. And yes, the answer to the example equation would be -7/3.
• was that the bite of 87
• yes, ofc it was
• How do you match a rational decimal?
• how can you solve this equation (7j+1/8q+3)-(5/8-11+2j)? Then also how can I showed my work fro this,do I just rigth the frist equation or slove the seconed equation.
(1 vote)
• First you should probably learn how to spell. Personally, I do not know how to solve this equation, but you should start there.