Answer:
4
Step-by-step explanation:
This is wanting you to put a numerator that will make this fraction bigger then 2/4.
2/4 is greater then 1/6, so that won't work
2/4 is greater then 2/6, so that won't work either
2/4 is equal to 3/6 because they reduce to 1/2, so it won't work
2/4 is less then 4/6, this will work
any number bigger then 3 can be put in the ? spot
