Adding and subtracting fractions

A complete lesson for first teaching how to add and subtract fractions with different denominators. Does include some examples and questions involving simplifying at the end, but doesn’t include adding or subtracting mixed numbers.

Activities included:

Starter:
Some quick questions to test if pupils can find equivalent fractions and identify the lowest common multiple of two numbers.

Main:

• Some examples with diagrams to help pupils understand the need for common denominators when adding.
• A recap/help sheet of equivalent fractions for pupils to reference while they try some simple additions and subtractions. At this stage, they aren’t expected to find LCMs ‘properly’, just to find them on the help sheet.
• Some example question pairs on adding or subtracting by first identifying the lowest common denominator, starting with the scenario that the LCM is the product of the denominators, then the scenario that the LCM is one of the denominators, and finally the scenario that the LCM is something else (eg denominators of 4 and 6).
• A set of straightforward questions with a progression in difficulty. The hardest ones require students to simplify the answer.
• A challenging extension where pupils must find four digits to fit a given fraction sum.

Plenary:
A final example designed to challenge the misconception of adding numerators and denominators, and give a chance to reinforce the key method.

Worksheets and answers included.

Please review if you buy as any feedback is appreciated!