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.

### Course: 4th grade (Eureka Math/EngageNY)>Unit 5

Lesson 6: Topic F: Addition and subtraction of fractions by decomposition

# Fraction word problem: lizard

Sal solves a fraction word problem about the length of a lizard.  The fractions have common denominators.  Created by Sal Khan.

## Want to join the conversation?

• is multiplication of fractions same as adding fractions
• Also, when you multiply two fractions less than one, your answer actually gets smaller. Think about the multiplication sign as saying "groups of." 3 x 8 = 24 means 3 groups of 8 are 24.

With fractions, you're still saying that. 1/2 of a group of 12 is 6. 1/3 of a group of 9 is 3.

The procedure for two fractions is to multiply across -- numerator times numerator and denominator times denominator.

1/2 x 2/3 is saying that you have half of a group that was 2/3 of a full group to begin with. So, you had 2 thirds, but not you only have half of that, or 1/3

numerators : 1 x 2 = 2
denominators: 2 x 3 = 6

So the answer is 2/6, which can be reduced to the equivalent fraction 1/3.
• so 3/4 of an hour is 45 min right?
• yes an hour has 60 min so 1/4 of an hour is 15 min so multiply that by 3 and you get 45
• Does the end result have to be a mixed fraction?
• Not always. It could be a decimal for example.
• how can you ad the tail and body together shouldent it be head body and tail?
• It could be, but your head if part of your body right? I think he just counted the head as part of the body too.
(1 vote)
• wouldnt the fractions need to be changed to a mixed number
• You COULD turn them into mixed numbers, but you don't NEED to. Often, fractions are easier to work with if they're improper fractions instead of mixed numbers.
• A child's ladder is made of 3 sections each section is 3/4 meters long how long is the ladder when 3 sections are extended to make 1 ladder?
• I received a quiz question which asked me to double 5/8. I assumed the answer would be 10/16. However, it was 5/8 x 2/1 = 10/8. Can someone please explain why 10/16 is incorrect and why 10/8 is correct?
(1 vote)
• 10/16 is incorrect and why 10/8 is correct John. When the question asked you to double, it means to multiply it by 2. When you multiply fractions, the bottom number doesn't change. So, you would multiply 5*2 and get 10. Then, add your denominator. Your correct answer is 10/8! I hope you understand.
(1 vote)
• is multiplication of fractions the same as adding fractions?
(1 vote)
• No. To multiply fractions, we multiply numerators and multiply denominators. If any numerator and any denominator have a common factor (other than just 1), we have the option of dividing that numerator and that denominator by the common factor to make the fraction multiplication problem easier.

Have a blessed, wonderful day!