Explain why you cannot add fractions with unlike denominators? - Answers

You can totally add fractions with unlike denominators. You have to first find the LCD (least common denominator) to make them the same denomintars. And then you can just simply add them. What you cannot do is add fractions with unlike denominators without changing them to fractions with like denominators. The reason being that you would be attempting to add fractions that are different sizes. 1/2 is not the same size as 1/3, so it would be like trying to add apples and Oranges. You have to change them to a common size and that is the reason you have to find the least common denominator first. While you cannot add 1/2 and 1/3, you can add 3/6 and 2/6.