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
5 Things to Know About Fighting ISIS | Explorer
[Music] The Kurds are often described as the largest, the world’s largest ethnic group that does not have a country of its own. Most people put the population of Kurds at about 30 million, and they’re spread through at least four countries: Syria, Turkey,…
How to sell a $15,000,000 private jet!
How much you want to spend? Budget of 10 to 15 million. You really have a lot of choices. How many people you want to carry? Probably max eight people. How much do you think you’re flying a year? I’m probably flying three times a week. I’ve always flown …
How I make SIX FIGURES from posting Real Estate listings on Craigslist
What’s up you guys, it’s Graham here. So, some of you may already know, I pretty much built my entire real estate business by posting leases on Craigslist. From that, I’ve been able to make over six figures per year consistently from clients that I’ve ori…
High Speed video of Canon DSLR Shutter - Smarter Every Day 40
Hey, it’s me Destin. Welcome to Smarter Every Day, and a blood vessel exploded in my eye. It’s pretty cool. It’s called a subconjunctival hemorrhage. I think it’s pretty neat. Anyway, so today I’m gonna show you a little experiment that I’m doing right b…
shower thoughts that really confuse me..
Wow, another shower thoughts video; who would have guessed? Not like the last two got a million views or anything. Look, I’m just trying to make people smile or something. You know, people say that a child’s laughter can light up your home, unless it’s 3:…
How To Get Rich In Your 20s (Realistically)
What’s up guys, it’s Graham here. So unfortunately, it’s widely believed that Millennials are the most financially screwed generation in history. After all, mortgage rates are at their most expensive level since 2001. Food prices are rising at the fastest…