Lately the US dollar has been very weak against the GBP and moreso than previously I've seen in the course of years. In the past I've seen the pound be from either 1.25 dollars to 1.50 dollars, but lately it has been hovering at the level of 1.99 dollars, sometimes teetering at the 2.00USD mark. Which means that the pound buys more than the dollar can buy. And when in commerce an American has to double the rate of pounds mathematically to find the arithmatic value in US dollars. Conversely and to the point of your question, the number of USD dollars is half the digits of GBP's. One dollar is one half a pound. Two dollars is one pound. There are adjustments because the rate changes daily.
