# Python script that increases a number by a percent

So, I've been working on this project for quite a while, and I can't seem to figure this out. I've written the script for increasing a number by a percent, but I keep getting this error:

``````File "C:\Users\jacob\Python Scripts\Percent.py", line 11, in <module>
value = str(num + ((num / 100) * percent))
TypeError: unsupported operand type(s) for /: 'str' and 'int'
``````

I don't know why this is happening, but here's my code.

``````value = ""
print("Number increase or decrease by percent")
print("")
print("Increase or decrease:")
input = input()
if (input == "increase"):
print("Number:")
num = input()
print("Percent:")
percent = input()
value = str(num - ((num / 100) * percent))
print(value)
if (input == "decrease"):
print("Number:")
num = input()
print("Percent:")
percent = input()
value = str(num - ((num / 100) * percent))
print(value)
``````

Any help would be greatly appreciated, I'm still a noob.

## 2 answers

• answered 2021-04-08 03:17

`if` statements do not need parentheses in Python. Also, don't repeat yourself. You had identical code in both branches. And if you're doing a multiply and a divide, do them in that order to avoid loss of precision. Also, when you're increasing by a percentage, you generally want to add, not subtract.

``````print("Number increase or decrease by percent")
print("")
print("Increase or decrease:")
option = input()
print("Number:")
num = int(input())
print("Percent:")
percent = int(input())
if option == "increase":
value = num + (num * percent / 100)
if option == "decrease":
value = num - (num * percent / 100)
print(value)
``````

• answered 2021-04-08 03:18

`input()` returns a string, you have to convert the input string to `float`, and you should not let `input = input()`. The code below should work:

``````value = ""
print("Number increase or decrease by percent")
print("")
print("Increase or decrease:")
option = input()
if (option == "increase"):
print("Number:")
num = float(input())
print("Percent:")
percent = float(input())
value = str(num + ((num / 100) * percent))
print(value)
if (option == "decrease"):
print("Number:")
num = float(input())
print("Percent:")
percent = float(input())
value = str(num - ((num / 100) * percent))
print(value)
``````