From Yahoo Answers

**Question:**How to? Easy instructions would be very much appreciated!

**Answers:**First, turn all mixed fractions to improper to make it easier. Second, make them all have a common denominator. Third, you can finally add or subtract. Last (if needed, turn back into mixed fraction) Example: 4 1/2 + 3 1/3 (example problem) 9/2 + 10/3 (changing to improper) 27/6 + 20/6 (common denominator) 47/6 (answer in improper form) 7 5/6 (answer in mixed number form) Example: 5 1/5 - 1 3/4 (example) 26/5 - 7/4 (improper format) 104/20 - 35/20 (common denominator) 69/20 (answer in improper form) 3 9/20 (answer in mixed number form)

**Question:**I know this sounds really stupid, but me and my mom are having an argument about how to do simple third grade math.I'm in 7th grade and never learned fractions right. Here's the question : 5/9 = 2 3/4. I thought you changed the mixed number into an improper fraction, add the fractions together, and then divide your numerator by the denominator (since the top on is bigger in this case) and what you got would be the whole number, then the number after the point would be the numerator, then the denominator would be the same.

**Answers:**First of all 2 3/4 does NOT equal 5/9. The improper fraction for it would be 11/4 (you multiply 2 times 4 and add the 3, so you have 8 +3 =11, and place it over the 4 to give you the 11/4. 5/9 is a proper fraction by itself. 9/5 would be the improper fraction because it comes out to 1 4/5. To add together 5/9 and 2 3/4: 1. change the improper fraction to 11/4 2. find the **lowest common multiple between the 2 of them, which in this case is 36. (http://www.mathsisfun.com/least-common-multiple-tool.html) 3. change 5/9 to 20/36 (9 times 4 = 36 and 4 times 5=20). 4.do the same for 11/4 (4 times 9 =36; 11 times 9 =99) to make 99/36 5. add the two together : 20/36 + 99/36 (keeping the same denominator ) to equal 119/36. 6. Reduce the 119/36 (3 times 36 = 108), so you have 3 11/36 as your answer because 11/36 cannot be reduced any further. For more "expert help" go to http://www.mathsisfun.com/fractions_addition.html Other topics at the site: Introduction to Fractions Simplifying Fractions Equivalent Fractions Least Common Multiple Least Common Multiple Tool Least Common Denominator Subtracting Fractions Multiplying Fractions Dividing Fractions Fractions Index **Definition of Least Common Multiple, with examples: http://www.mathsisfun.com/least-common-multiple.html

**Question:**so if u have exponents, what the rule with adding/multiplying them? if i add x + x will i get x squared? what if i add x squared + just x? i am still really confused with these... please explain it all to meeee :) thanks!!!

**Answers:**Okay the easiest way to get started with adding and multiplying variables and variables with exponents is to not imagine "X" not as a number but as something being multiplied by a number, for example. (This works for ADDING AND SUBTRACTING NOT MULTIPLICATION OR DIVISION) X can be written as 1X. When adding X's together do not worry about the X's just worry about the numbers that are in front of it. X + X = 2X because it is really 1X + 1X = 2X. Same goes for other additions; X + 2X + 5X = 8X because it is really 1X + 2X + 5X = 8X. Don't worry about the X's in these situations where the X is the same just add the numbers in front, but NEVER add X's when the X's DO NOT match, For example: You cannot do this: x^2 + x = 2x^2 this is wrong. To get an x^2 you need to multiply two x's together. For example: X*X= x^2. This is an interesting case because the X's powers add; here's what I'm saying: x * x = (x^1) * (x^1) = x^2. The ones add and you get a power of two. This is true in other cases when these numbers are MULTIPLIED or DIVIDED not ADDED or SUBTRACTED a harder one is x^2 * x^2 * x^10 = x^14 because 2+2+10=14. You can even do a problem like this 2x^2 * x^2 * x^10 = 2x^14 the 2 is carried to the answer when you multiply two numbers like this. 2x^5 and 5x^5 the first number is multiplied and the top number is added 2x^5 * 5x^5 = 10x^10. Be careful not to mix up addition and multiplication in these cases. remember this way. When adding and subtracting X's only the front number -----THIS ONE----> (2)x^2 is effected, when multiplying both numbers are effected. Here are some examples to help you get the idea. They get more complicated as the go. (1)X + (1)X + (1)X = 3X 2X + 4X -5X = X X + 3X + 2x^2 = 4X + 2x^2 (You can't add 4x and 2x^2 together because they have different powers) X * X * X = x^3 x^2 * x^6 * x = x^9 2x^2 * 4x^2 * x^2 = 8x^6 (The front two numbers are multiplied.) 2x^6 * 3x^2 + 2x = 6x^8 + 2x (You cannot add 2x because it has a different power.) 2x^6 * 3x^2 + 2x^8 = 6x^8 + 2x^8 = 8x^8 (You can add these because they have the same power.)

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