Look at a golf leaderboard, on TV or in person at a tournament, and you'll see numbers (usually) in two colors: red and black.
So what do those red and black numbers mean on a golf leaderboard?
Quite simply, red and black numbers differentiate scores which are under par and scores which are over par. If a number posted on a leaderboard is red, then the score is under par. If a number posted in black, then the score is over par (or even par). Sometimes, particularly at the Masters, scores of even par are posted in green numbers or lettering.
This is done so golf fans can easily look up at a leaderboard and understand the scoring, as well the par for a particular hole. A number of leaderboards on the PGA Tour show hole-by-hole scores, so you can see the charting of scoring as a round and tournament progresses.
On the Masters leaderboard, particularly on their website, you can see scores for each hole posted as well, showing under par scores for a hole in red, a score of par on a hole in green and an over par score on a hole in black. In fact, the idea of red and black numbers were invented for use on golf leaderboards at Augusta National Golf Club.
Red and black figures are also fairly easy to understand from the world of business. In a business ledger, red figures mean a loss because they represent a negative number. Black numbers on the ledger are positive. However, the meaning is the opposite in golf. Negative numbers are good in golf. Positive numbers are bad in golf.
These red, black and green numbers are a better visual cue for fans, but golfers can also use shapes around their scores to indicate over and under par scores as well. If you look at a golf scorecard and see a circle around a score for a hole, that means the player was 1 under par for that hole. Two circles? Then 2 under par, and so forth. On the other hand, squares around a score are bad. A single square around a score means a 1 over par score of bogey, and so forth. No shapes around a single hole score indicate a score of par.