To find the percentage change from 100 to 800, we need to first calculate the difference between the two numbers.

Step 1: Difference = Final Value - Initial Value

Difference = 800 - 100

Difference = 700

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 = |700|

Absolute Difference = 700

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

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

Percentage Change = (700 / 100) x 100

Percentage Change = 700%

Therefore, the percentage change from 100 to 800 is 700%. This means that there was an increase of 700% from 100 to 800.