To find the percentage difference between two numbers, we first need to calculate the absolute difference between them. In this case, the absolute difference between 40 and 52 is 12.

Next, we need to find the average of the two numbers. The average of 40 and 52 is (40+52)/2 = 46.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 40 and 52 is (12/46) x 100 = 26.09%.

This means that 52 is 26.09% higher than 40, or that 40 is 26.09% lower than 52.