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 156 and 180 is 24.

Next, we need to find the average of the two numbers. The average of 156 and 180 is (156+180)/2 = 168.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 156 and 180 is (24/168) x 100 = 14.29%.

This means that the second number, 180, is 14.29% higher than the first number, 156.