yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

How to subtract mixed numbers that have unlike denominators | Fractions | Pre-Algebra | Khan Academy


2m read
·Nov 10, 2024

Let's try to evaluate 7 and 6 9ths - 3 and 25ths.

So, like always, I like to separate out the whole number parts from the fractional parts. This is the same thing as 7 + 6/9 - 3 - 25/100. The reason why I'm saying -3 and -25/100 is this is the same thing as -3 + 25/100.

So, you distribute the negative sign: you're subtracting a 3 and then you're subtracting the 25/100. Now we can worry about the whole number parts: 7 - 3. Well, 7 minus 3 is going to give us 4. So that's going to give us 4.

Then we're going to have 6/9 - 25/100. Let me think about what 6/9 - 25/100 is. We're going to have to find a common denominator. The least common multiple of 9 and 100 is going to be 900.

Now, they have no common factors, so it's going to be over 900. To go from 9 to 900, I have to multiply by 100. So, I'm going to have to multiply the numerator by 100: 6 * 100 is 600.

To go from 100 to 900, I had to multiply by 9, so I have to multiply the numerator by 9 if I don't want to change the value: 25 * 9 is 225.

So, 600/900 - 225/900 is going to be something over 900. 600 minus 225 is 375. So this is, if I subtract these two fractions right over here, I get 375/900.

So it's 4 + 375/900. If we wanted to write it as a mixed number, this is equal to 4 and 375/900, but we're not done yet.

We can simplify this further: 375 and 900 have common factors. They are both divisible by 75. So, we can say that this is actually...

If we divide the numerator by 75 and the denominator by 75, we end up with 4 and 375/75 is 5, and 900/75 is 12.

So we have 4 and 5/12. Actually, we're done. These two can't be simplified anymore: 4 and 5/12.

More Articles

View All
7 Most ANNOYING Online Gamers: V-LIST #3
Hey everyone! I’m Lacy, and this is BTW on Bauce. This week, I’m talking about online gaming, specifically the people that you meet online. You know exactly who I’m talking about. They’re the people that are always there, and they always annoy you, and ye…
Is Your Red The Same as My Red?
Hey, Vsauce. Michael here. This appears blue. This appears yellow. And this appears green. Those of us with normal color vision can probably agree. But that doesn’t change the fact that color is an illusion. Color, as we know it, does not exist in the out…
Hindu gods overview | World History | Khan Academy
Hinduism is often known for its large and complex pantheon of gods. The goal of this video is to give an overview of them and to think about how they are connected and how they are perceived. So, the Hindu Trinity, as it is often called, is made up of Sh…
Factoring using polynomial division: missing term | Algebra 2 | Khan Academy
We’re told the polynomial ( p(x) ) which is equal to this has a known factor of ( x + 6 ). Rewrite ( p(x) ) as a product of linear factors. Pause this video and see if you can have a go at that. All right, now let’s work on this together. Because they gi…
Ray Dalio’s Best Advice for Young Entrepreneurs
You’re a role model for so many young people who want to be like you. They’re thinking by being like you means extraordinarily rich, but they’re not looking at these deeper questions. What would you say to all these young entrepreneurs who are, you know, …
why Japanese people are so healthy and long living? 🇯🇵
The average life expectancy in Japan is 84 years according to the OECD. Japanese women can expect to live to the age of 87, 6 years more than their counterparts in the U.S. Japanese men can expect to live to 81, five years more than their American peers. …