Algebraic expressions in fraction form are rational. Methods of adding, subtracting, multiplying and dividing fractions plus expanding and factorising can be used to simplify rational expressions.

Learn the meaning of like and unlike terms and simplify algebraic expressions by collecting like terms with this BBC Bitesize Maths article. For students between the ages of 11 and 14.

Many mathematical operations are easier to handle in this way. “For instance, expression simplification amounts to finding a shorter equivalent representation of a tree,” say Lample and Charton.