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
1998 Berkshire Hathaway Annual Meeting (Full Version)
[Applause] Morning! [Applause] Good morning, I’m Warren Buffett, chairman of Berkshire, and this is my partner. This hyperactivity fellow over here is Charlie Munger. We’ll do this as we’ve done in the past, following the Saddam Hussein School of Manageme…
m͏̺͓̲̥̪í͇͔̠ś̷͎̹̲̻̻̘̝t̞̖͍͚̤k̥̞à̸͕̮͍͉̹̰͚̰ẹ̶̢̪s͏̨͈̙̹̜͚̲ ̛̬͓͟
Hey, Vsauce. Michael here. The title of this video is misspelled in honour of mistakes. Mistakes are everywhere; they surround us like air. To err is human. Faults, flaws, faux pas, fumbles and fallacies are as much a part of who we are today as the stuff…
Buying a $45,000,000 Home In Los Angeles
[Music] Foreign [Music] How’s it going bud? Good to see you! Blowing up lately? We’re doing our best. We’re doing properties all around the world and I’m really excited that you’re here. I know last time we met we talked about doing a video together. We…
Joel McHale in a Slot Canyon | Running Wild With Bear Grylls
[music playing] OK, this is going to be tight. BEAR GRYLLS (VOICEOVER): Comedian and actor Joel McHale and I are trying to navigate a deep slop canyon in the Arizona desert. Oh my god. BEAR GRYLLS (VOICEOVER): But it just became dangerously narrow. Oh…
Did People Used To Look Older?
Hey, Vsauce! Michael here. At the age of 18, Carl Sagan looked like a teenager. But it doesn’t take long in an old high school yearbook to find teenagers who look surprisingly old. These people are all in their 20s, but so are these people. This is Elizab…
Courage | The Art of Facing Fear
Sometimes even to live is an act of courage. Seneca. Is kicking your enemy into a large well after screaming “This is Sparta” the Hellenistic embodiment of courage? Well, it could be, looking at the Greek mythological heroes like Achilles and Hector, and …