Answer:
3
Explanation:
Start by listing all the numbers 48 and 81 are divisible by
48: 1,2,3,4,6,8,12,16,24,48
81: 1,3,9,27,81
Now that we have all those listed look between the two and find the largest number that shows up on both lists, in this case it is 3
I hope this helps and please don't hesitate to ask if there is anything still unclear!