To find the percentage change from 50 to 45, we need to first calculate the difference between the two numbers.

Step 1: Difference = Final Value - Initial Value

Difference = 45 - 50

Difference = -5

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 = |-5|

Absolute Difference = 5

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

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

Percentage Change = (5 / 50) x 100

Percentage Change = 10%

Therefore, the percentage change from 50 to 45 is -10%. This means that there was a decrease of 10% from 50 to 45.