After the polls closed in New Hampshire on Feb. 9, the Republican primary had a clear winner: Donald J. Trump. It took nearly two weeks for the state to award its 23 delegates, and in the end it gave Mr. Trump 11, John Kasich four, Ted Cruz and Jeb Bush three each and Marco Rubio two. But there’s a small problem: It looks as if New Hampshire gave Mr. Trump a delegate that actually belongs to Mr. Rubio.

To understand how this works, it helps to know that there are no national rules in the Republican Party for awarding delegates. Each state makes up its own rules.

In New Hampshire, the rules seem pretty straightforward. A candidate must get at least 10 percent of the vote to be eligible to win a delegate, a threshold cleared by both Mr. Trump (who earned 35.6 percent of the vote) and Mr. Rubio (who earned 10.6 percent). Then the candidates are awarded delegates in proportion to the total vote, with the statewide winner — in this case Mr. Trump — getting any delegates left unallocated.

But New Hampshire is somewhat bureaucratically creative where math is concerned. State law specifies the use of an unorthodox “double-rounding” process, in which you round each candidate’s vote percentage before multiplying by the number of available delegates, then round this product again to get the number of delegates won. Rounding Mr. Rubio’s vote up to 11 percent, multiplying this by 23 and then rounding this number yields three delegates.