30 - (30 / 100 * 30) =
30 - 9 = 21
Question: What is 30% off 30?
Step 1: Get the result of Number (30) / 100 * Percent (30).
30 / 100 * 30 = 9
Step 2: Subtract step one's result (9) from the number (30).
Result: 30% off 30 = 21.