To find the percentage difference between two numbers, we first need to find the absolute difference between them. In this case, the absolute difference between 27 and 275 is 248 (|27-275| = 248).

Next, we need to find the average of the two numbers. The average of 27 and 275 is (27+275)/2 = 151.

Now, we can find the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 27 and 275 is (248/151) x 100 = 164.23%.

This means that the second number (275) is 164.23% greater than the first number (27).