Tory Chief Whip In Belfast for DUP Talks

The transcript discusses the political situation in the UK following a general election stalemate. The Conservative Party, led by Prime Minister Theresa May, seeks support from the Democratic Unionist Party (DUP) to maintain power. A confidence and supply deal is proposed, where the DUP would support the Conservatives on key votes. Voter sentiments are mixed, with some critical of May's leadership. The DUP's influence on government policies is debated, and the arithmetic of needing their support for a majority is explained. Concerns about the partnership's stability are also raised.

What arithmetic reason is given for Theresa May needing to form a deal with the DUP?

What are the potential fears associated with the alliance between the Conservatives and the DUP?