Increase or decrease a number by "x" percentage-CodePudding

How do I increase or decrease an "X" number by a certain amount of percentage say, 2% or 3%?

Case scenario: My value is 5 - I want to increase this number by 2% - so the final value will be 5.1 after 2% percentage increase.

And the same would be if I want to decrease this number by an "X" percentage.

I hope that makes sense, thank you.

CodePudding user response：

To calculate a percentage in Python, use the division operator (/) to get the quotient from two numbers and then multiply this quotient by 100 using the multiplication operator (*) to get the percentage.

y=int(input("Enter Percentage: "))
x=5
x  = (x * y/100)
print(x)

Output:

Enter Percentage: 2
5.1

For Decreasing Value:

y=int(input("Enter Percentage: "))
x=5
x -= (x * y/100)
print(x)

Output:

Enter Percentage: 2
4.9

CodePudding user response：

A percent is just a fraction of 100, so multiply by 1 your percent over 100:

>>> x = 5
>>> x *= (1   2/100)
>>> x
5.1

Another way to think of it is incrementing x by x times that percent (these operations are algebraically equivalent):

>>> x = 5
>>> x  = (x * 2/100)
>>> x
5.1

CodePudding user response：

If you want to increase by a percent, multiply the number by (1 {percent}). To decrease by a percent, multiply the number by (1-{percent}). Given your example:

Increase 5 by 2%: 5*(1 0.02)=5*1.02=5.1
Decrease 5 by 2%: 5*(1-0.02)=5*0.98=4.9.