Answer:
12
Step-by-step explanation:
We want the smallest possible number that can be divided by both 4 and 6 with no remainders.
12 is the least common multiple (LCM) of both 4 and 6, meaning it's the smallest number that 4 and 6 both divide into evenly.
24 could be used as a common denominator, but it isn't the <em>least</em> common denominator. It has more prime factors than is necessary to be the LCD.
12, when its prime factorization is written out, is 2² • 3.
24, when its prime factorization is written out, is 2³ • 3.
9/4 → (9•3)/(4•3) → 27/12
5/6 → (5•2)/(6•2) → 10/12
