Question: how to calculate percentage of amount in calculator?
Answer: If your calculator has a percentage button, the calculation is as follows: 40 x 25% = 10. If your calculator does not have a percentage button, you must first divide the percentage by 100: 25 ÷ 100 = 0.25. You can then multiply this answer by the whole to determine the part: 0.25 x 40 = 10.