Subtracting Fractions with Different Denominators

This video tutorial explains how to subtract fractions with different denominators by finding a common denominator. It provides three examples: 5/6 - 2/9, 7/8 - 3/4, and 4/5 - 2/3, demonstrating the process of finding the lowest common multiple and adjusting numerators accordingly. The tutorial concludes with an interactive exercise encouraging students to identify mistakes in fraction subtraction.

In the example of 7/8 take away 3/4, what is the common denominator used?

What mistake can be spotted in the subtraction of the fractions presented at the end?