Many students have been taught to add and subtract fractions using "tricks". Unfortunately, tricks that work with arithmetic, don't transfer well to algebra. After successfully completing this work, you'll be able to find the Least Common Denominator (LCD), build equivalent fractions using the same thought process you'll need for algebra and add and subtract fractions with unlike denominators.
Adding and subtracting fractions that have a common denominator
How to build the Least Common Denominator (the LCD)
How to build equivalent fractions