What did i do wrong it fails 2 of the tests

Question

Mathematics
Find which math expression matches the answer that you are given, if you have an integer answer, and a list of math expressions.

Task:
Test each math expression to find the first one that matches the answer that you are given.

Input Format:
Two inputs: an integer and a space separated string of math expressions. The following operations need to be supported: addition +, subtraction -, multiplication *, division /.
An expression can include multiple operations.

Output Format:
A string that tells the index of the first math expression that matches. If there are no matches, output 'none'.

Sample Input:
15
(2+100) (5*3) (14+1)

Sample Output:
index 1
https://code.sololearn.com/c0Huic0Mu4Uz/?ref=app

Answer 1

Costy Game
Two or three reasons I can think of:
15
(-5+20)
you output none due to:
while(a>0){
a/=10;
nr++;
}

another one, "An expression can include multiple operations" means:
15
(3+2+10)
again, output none.

another thing is that you might need to take into account operators precedence.

There might be more...
btw choose better and clear names for your variables.