Three percentage sums in one place. Find X% of a number, work out what share one number is of another, or measure the percentage rise or fall between two values.
How do I find a percentage of a number quickly?
Move the decimal two places left and multiply. 15% of 2,500 becomes 0.15 x 2,500 = 375. For 10% just move the decimal one place: 10% of 2,500 is 250, and 5% is half of that.
Why is a 20% fall not undone by a 20% rise?
The two sums start from different numbers. ₹1,000 falling 20% gives ₹800. A 20% rise on ₹800 is only ₹160, taking you to ₹960. You need a 25% rise to get back to ₹1,000.
What is the difference between percent and percentage points?
If a rate moves from 4% to 6%, that is a rise of 2 percentage points, but a rise of 50 percent. News reports mix the two constantly. Use points when you are comparing two percentages.
How do I remove GST from a price that includes it?
Divide, do not subtract. For 18% GST, divide the total by 1.18. A ₹1,180 bill has a base price of ₹1,000 and ₹180 of tax. Taking 18% off ₹1,180 gives the wrong answer of ₹967.60.
How do I calculate my exam percentage?
Use the second mode. Enter your total marks as the part and the maximum marks as the whole. 456 out of 600 is (456 / 600) x 100 = 76%.
How do I work out a discount before I reach the till?
Find 10% by moving the decimal one place, then scale it. For 30% off ₹1,850: 10% is ₹185, so 30% is ₹555, and you pay ₹1,295.