Question

How can you quickly calculate 20 percent of any bill amount?

Answer 1

Move the decimal point in your pretax bill one place to the left to get $5.375 from $53.75.Round up to the next easy number: $5.40.Double that number to get $10.80, which is 20% of your original bill.

Answer 2

There are many ways to do this calculation. Few are listed below.

1. Whenever we say percent, that means divided by hundred. And any number divided by 100 will result in putting a decimal to two places left. Like 20% will becomes
`(20)/(100)` = 0.20

And you can multiply the bill amount with 0.20 mentally.

2. You can also simply divide the total bill amount by 5, it will be equal to 20% of the total bill amount. Like if bill amount is $200.

`(200)/(5)=40` and
`0.20*200=40`. Both values are same.