Adding and Subtracting Fractions This is the thing that might get complicated. Don’t worry though, I heard that your teacher is amazing Let’s Get … Visual 1 2 3 In the same way, we can add fractions 1 1 2 2 2 2 Let’s get … Visual What we need to know … • When adding or subtracting fractions, ONLY add or subtract the Numerator. • REMINDER, in case the above rule wasn’t clear: DO NOT TOUCH THE DENOMINATOR • For example … This is correct. Hip Hip Hooray. 2 1 3 4 4 4 This is WRONG. Don’t be this guy 2 1 3 4 4 8 Same thing for Subtraction. Good work kids 2 1 1 4 4 4 Again, don’t do this. Seriously, who is this guy? 2 1 1 4 4 0 Now … for the tricky part. • What if the denominators are different?!! • Are we doomed? Are we in trouble? Oh the humanity!! Chill out, you’re fine. Like seriously, relax • It is called “Finding a Common Denominator” • Remember that thing about Equivalent Fractions and multiplying by one and all that goodness? What about LCMs? • Yeah, that is going to be super important for this lesson. Some things to Remember • If the Denominators are not the same, YOU CANNOT ADD OR SUBTRACT THEM • But, there is a way to make them the same, and that is multiplying that fraction by one • Aren’t we tricky? 2 1 5 10 2x2 5x2 1 10 ? 5 10 2 1 3 6 5 1 12 4 9 1 14 7 ? ? ? 2 1 3 6 5 1 12 4 9 1 14 7 ? ? ? 5 1 8 2 2 2 3 9 13 1 15 5 ? ? ? 5 1 8 2 2 2 3 9 13 1 15 5 ? ? ? 1 1 2 3 2 2 3 4 13 1 15 10 ? ? ? 2 1 12 18 5 1 12 9 9 1 14 21 ? ? ? A thing about Denominators • If worse comes to worst, just multiply the two different denominators together. • If you do this, you are not guaranteed a LOWEST common denominator, but you are guaranteed a COMMON denominator, which is all that you actually need for adding and subtracting fractions.