Due to his ....... to add up properly, he made a big mistake in the accounts book

1. due to his ....... to add up properly, he made a big mistake in the accounts book ((in) able)
2. I ...... with what you are saying. In fact I am of the exact opposite opinion. (qgree) 3
3. He was made many successful ... investment (finance)
4. That man is involved in lots of ....... but the police can't prove anything at the moment (legal)