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# Multiplying 2 fractions: number line

Sal uses a number line to multiply fractions. Created by Sal Khan.

## Want to join the conversation?

• At , doesn't Sal mean the two halves?
• He's dividing the halves into fourths
• Why does he make this more confuseing than it needs to be?
• Then look at other video! He is trying his best!
• I do not understand this. Could you make more simpimler? Please?
• multiple the top by the top and multiple the bottom by the bottom
(1 vote)
• The Number Line approach is interesting but its hard to do unless you have a notebook and pencil with you but in the case where you have to quickly solve a question like "If the tax refund (lets say 1200$) is being divided between 4 people, how large of a fraction is each person getting?", and you don't happen to have a pencil and notebook by your side, how could you more easily do a question like that in your head? (5 votes) • If you're dividing 1 whole among 4 people, then each person gets 1/4 of whatever it is you're dividing. Something tells me that's not what you meant, though. Because 1200 is a nice multiple of 100, we can simply drop the zeroes and add them back later on. The problem then changes from 1200/4 to 12/4. 12/4 can be simplified to 3 (4 + 4 + 4 = 12), and then tack the zeroes back on - we get a result of$300.
• umm i don't understand how it become 1/8 2/8 3/8 in number line ?
• On the number line, there is an increase (increment) of 1/8 each time. Each time a 1/8 is added, there will be that increase (e.g. after adding 1/8 to 0, the result is 1/8; after adding a 1/8 to the already present 1/8, the result is 2/8; adding another 1/8 to the 2 one-eighths gives a 3/8; adding yet another 1/8 to the 3 one-eighths gives a 4/8, etc.)
• When i'm adding fractions do I need to add the numerator
• no you need to find a common bottom number and that
(1 vote)
• i lik tis epizode it relly halped
• can you do the same with division?