Soulver helps you work out percentages more easily. Here are some examples:

You see all Soulver's percentage phrases by holding down the % key on iPhone, or by turning your device to landscape and tapping the "%" tab on iPad.

Here they are with descriptions of how they work:

Operation	Example	Result
Percentages on, of, off numbers
Adding a percentage to a number	$100+10% 10% on $100	$110
Percentage of a number	10% of 200 10% * $200	$20
Subtracting a percentage from a number	$100-10% 10% off $100	$90
Numbers as percentages on, of and off each other
One number as a percentage on another	220 as a % on 200	10%
One number as a percentage of another	30 as a % of 200 30/200%	15%
One number as a percentage off another	30 as a % off 200	85%
Calculating the original number given a final number and percentage change
Mark up	10% on what is $200	$181.82
Mark	10% of what is $200	$2,000.00
Mark down	10% off what is $200	$222.22
Calculations with pure percentages
Adding & subtracting percentages	100% + 45% 90% - 30%	145% 60%