Final answer:
A golfer marking two numbers per hole has scored a double bogey. A double bogey is two strokes over par, whereas a birdie and a bogey are one stroke under and over par, respectively.
Step-by-step explanation:
When a golfer marks two numbers per hole, it typically means that they have scored a double bogey. In golf scoring, a double bogey indicates that the golfer has taken two strokes more than par to complete the hole. Par is the predetermined number of strokes that an expert golfer is expected to require to complete a hole. A birdie is one stroke under par, a bogey is one stroke over par, and a double bogey is two strokes over par. As a point of comparison, a hole-in-one, also known as an ace, occurs when a golfer sinks the ball with one stroke.