:: StoryTitle
Fairmath System in Harlowe

:: Start
<!-- Fairmath formulas based on http://choicescriptdev.wikia.com/wiki/Arithmetic_operators#Fairmath -->

<!-- Set an initial value for the story -->
(set: $valueToAdjust to 100)
The initial value is $valueToAdjust.

<!-- Set originalValue to the value to adjust -->
(set: $originalValue to $valueToAdjust)
<!-- Set the changeValue (percentage) to adjust -->
(set: $changeValue to 50)
<!-- Display (call) the Fairmath Decrease passage -->
(display: "Decrease")
<!-- The new value will be resultValue -->
The adjusted value is $resultValue.

<!-- Update valueToAdjust -->
(set: $valueToAdjust to $resultValue)
<!-- Set originalValue to the value to adjust -->
(set: $originalValue to $valueToAdjust)
<!-- Set the changeValue (percentage) to adjust -->
(set: $changeValue to 100)
<!-- Display (call) the Fairmath Increase passage -->
(display: "Increase")
The adjusted value is $resultValue.

:: Increase
(set: $resultValue to (round: $originalValue+((100-$originalValue)*($changeValue/100))) )

:: Decrease
(set: $resultValue to (round: $originalValue-($originalValue*($changeValue/100)) ) )