code_sol_four.py

def finder(arr1,arr2):
    
    arr1.sort()
    arr2.sort()
    
    for num1,num2 in zip(arr1,arr2):
        
        if num1 != num2:
            return num1
        
    return arr1[-1]
    
def finder(arr1,arr2):
    
    return sum(arr1) - sum(arr2)