In the last episode the team started investigating the following inquiry, sent in to curiouscases@bbc.co.uk: 'Is there any such thing as nothing?'
They discovered why quantum fluctuations and the Higgs field mean that nothing is impossible. But how about in mathematics?
The story of zero is fraught with inspiration, competition and controversy. Banned in Florence and hated by the Church, zero had a rocky road to acceptance after its genesis in India.
Hannah talks to author Alex Bellos and hears about his journey to India to see the birth of zero, featuring archive from 'Nirvana by Numbers' on BBC Radio 4.
Plus, Adam is sent on a mission to understand calculus and enlists the help of Jeff Heys from Montana State University.
If you have any Curious Cases for the team to solve please email curiouscases@bbc.co.uk
Presenters: Adam Rutherford & Hannah Fry Producer: Michelle Martin.