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Lesson 3: Adding and subtracting fractions: word problems

# Fraction word problem: pizza

Sal uses fraction models to figure out what fraction of a pizza is left. Created by Sal Khan.

## Want to join the conversation?

• True so what is numorator
• The numerator would be the number on top of a fraction like 2 in 2/3.
• I'm so bad at maths can someone teach me a easier way to do it
(1 vote)
• first try memorizing your subtraction and addition table and then try memorizing the multipication and division table. thats just a start
(1 vote)
• if the demonairs the same do i have to add the numerators?
(1 vote)
• Yeah, to figure out addition and multiplication using fractions, you have to make sure the fractions you are adding have common denominators, when they have common denominators, add or subtract numerators, but you answer will come out as a fraction. If you are multiplying fractions, you multiply numerator with numerator and denominator with denominator, then simplify. When you are dividing fractions, you flip the second fraction over and then multiply. I hope this helped:)
(1 vote)
• How do we know when we are wrong?/ some one help me
(1 vote)
• you know when your wrong if it does not have the same deomanater
(1 vote)
• How do you write a fraction with a tablet keyboard it won't recognise my answers
(1 vote)
• Also if this doesn't work you can try putting the fraction inside parenthesis. here's an example: (1/2) Because the slash also means division on the keyboard this helps for the device to identify it as a fraction, not a division problem. Hope this helps! :)
(1 vote)
• how do i acctually do this work instead of just watching videos. What do i search??//?
(1 vote)
• just click on "practice this concept" in the right hand side at the top of the video page. Hope this helped
(1 vote)
• if u really understand this u can do it in ur head
(1 vote)
• can a fraction equal 100