Adding & Subtracting Fractions With Different Denominators

Building upon last week's concept about what factions look like conceptually, this week I decided to visit the topic of adding and subtracting fractions that have different denominators. Although I somewhat remembered how to do it, the website Khan Academy really gave me a good refresher. The key word for these types of equations was finding the "Least Common Denominator" (LCM). After the quick video lesson, I was able to get through the problems with no issue!


Work: 3/5 + 1/2=?
LCM is 10 so the equation becomes 6/10 + 5/10= 11/10

 Work: 2/8 + 5/12 = ?
LCM is 24 so the equation becomes 6/24 + 10/24 = 16/24 but don't forget to reduce! so it becomes 2/3
 Work: 3/4 - 6/12 = ?
LCM is 12 so the equation becomes 9/12 - 6/12 = 3/12 = 1/4

Work: 8/6 - 5/4 = ?
LCM is 12 so the equation becomes 16/12 - 15/12 = 1/12

The link to the website is: https://www.khanacademy.org/math/arithmetic/fraction-arithmetic/arith-review-add-sub-fractions/v/adding-small-fractions-with-unlike-denominators

Next week, I'll be going through multiplying and dividing fractions, before moving on to a new topic!



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