To find the percentage change from 125 to 100, we need to first calculate the difference between the two numbers.

Step 1: Difference = Final Value - Initial Value

Difference = 100 - 125

Difference = -25

Step 2: Next, we need to find the absolute value of the difference. This is because percentage change is always calculated as a positive value.

Absolute Difference = |Difference|

Absolute Difference = |-25|

Absolute Difference = 25

Step 3: Now, we can calculate the percentage change using the formula:

Percentage Change = (Absolute Difference / Initial Value) x 100

Percentage Change = (25 / 125) x 100

Percentage Change = 20%

Therefore, the percentage change from 125 to 100 is -20%. This means that there was a decrease of 20% from 125 to 100.