To find the percentage change from 2500 to 800, we need to first calculate the difference between the two numbers.

Step 1: Difference = Final Value - Initial Value

Difference = 800 - 2500

Difference = -1700

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 = |-1700|

Absolute Difference = 1700

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

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

Percentage Change = (1700 / 2500) x 100

Percentage Change = 68%

Therefore, the percentage change from 2500 to 800 is -68%. This means that there was a decrease of 68% from 2500 to 800.