Subtract two columns in dataframe

Given the following dataframe:

import pandas as pd
df = pd.DataFrame([["Australia", 1, 3, 5],
                   ["Bambua", 12, 33, 56],
                   ["Tambua", 14, 34, 58]
                  ], columns=["Country", "Val1", "Val2", "Val10"]
                 )

It comes down to a simple broadcasting operation:

>>> df["Val1"] - df["Val10"]
0    -4
1   -44
2   -44
dtype: int64

You can also store this into a new column with:

>>> df['Val_1_minus_10'] = df['Val1'] - df['Val10']
>>> df
     Country  Val1  Val2  Val10  Val_1_minus_10
0  Australia     1     3      5              -4
1     Bambua    12    33     56             -44
2     Tambua    14    34     58             -44