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
Filming Glow-in-the-Dark Critters | Best Job Ever
[Music] Being a wildlife cameraman, it’s a whole discovery of technical knowledge. I’m working with Paul Merrick, who is a grantee of the National Geographic Society. Dr. Merrick studies millipedes, and we’re headed out to film them in their natural habi…
Fishing in the Yukon River | Life Below Zero
That’s a bourbon! Holy look, Maya! I got it! Yeah, you got it! Maya was able to pull out a lush, which was a big deal because it’s a different kind of fish. None of my kids ever seen one; I’ve never caught one, and I was really proud of her to be able to …
How Long Will You Live?
10,000 years ago, the average human life lasted just over 30 years, and then a hundred years ago that number was up to 50. If you were born in the last few decades in the developed world, then your life expectancy is 80 years. But that is, of course, assu…
Philosophy On Falling In Love
…bring suffering. If it’s merely a passing attachment, it can lead to more pain than joy.” He emphasizes that true love is unconditional and does not depend on the other person meeting our desires. Instead, it’s about caring deeply for another’s well-bein…
How I started my business. 📈
How did you end up in London and why London? I read originally you’re from New York. Yeah, I am from New York. I left the business for a while. I was in private equity, working with guys doing some corporate takeovers. And then I decided to get back into…
The Warning Of Hyper Inflation | DO THIS NOW
So, as most of you know, I usually intro my videos with “What’s up, you guys? It’s Graham here.” But the only thing up today is inflation, and it’s getting much, much worse than most of us initially expected. Throughout the last week, it was revealed that…