Conversation so far:
When was Rosalind Franklin born?
25 July 1920.
Where was she born?
50 Chepstow Villas, Notting Hill, London.
Did she have any hobbies?
Rosalind is alarmingly clever - she spends all her time doing arithmetic for pleasure, and invariably gets her sums right.

Question: She did this as a child?
Self-contained rewrite: Rosalind Franklin did arithmetic for pleasure as a child?