Darts players add up scores quickly by recognising patterns, memorising common visits and learning checkout routes rather than doing fresh maths every throw.
Darts starts on 501 because the odd number works well with double-out finishing, creates better checkout routes and adds tactical pressure to every leg.
The most 180s in a PDC World Championship match is widely recorded as 42 combined maximums, hit by Gary Anderson and Michael van Gerwen in the 2017 final.
If a dart hits another dart, the score depends on where it finishes. Here are the rules for deflections, bounce-outs, knocked-out darts and darts hanging from another dart.