MSP Babowlers
Three balls a frame in frames 1-9, up to four deliveries in the 10th - here is what each ball is worth, with worked examples.
A duckpin scoresheet has ten frames, and each frame has room for three balls. Mark the pins for each ball as it is thrown. If the frame stays open - pins still standing after three balls - the frame scores exactly the pins knocked down, with no bonus of any kind.
A strike ends the frame on the first ball: all ten pins down, scored as 10 plus the pins on the next two balls. A spare ends the frame on the second ball: the rest of the ten cleared, scored as 10 plus the next ball. The third ball exists only for frames where ten pins refuse to fall in two tries.
Worked example, open frame: you knock 4, then 3, then 2. The frame scores 9. Nothing carries forward, nothing carries back - the box simply reads 9.
On narrow screens, swipe or scroll the plate sideways.
Worked example, spare: you knock 7, then the remaining 3. The frame is worth 10 plus your next ball; if that next ball is a 6, the spare frame scores 16, and the 6 also starts the next frame.
Worked example, strike: 10 plus the next two balls - if those are 8 and 1, the strike frame scores 19. In the 10th frame the same bonuses apply, which is why a strike or spare there earns a fill ball: the frame can run to three balls plus that extra delivery so the bonus has balls to count.
Three scoring errors account for most disputed sheets. The dropped fill ball: forgetting the extra 10th-frame delivery after a strike or spare. The phantom bonus: adding the third ball's pins as a bonus after a spare, when a spare only ever adds the next one ball. The erased foul: leaving a fouled delivery blank instead of recording 0. For the measurements behind these numbers, see Duckpin vs Tenpin: Lane, Pins, Ball and Rules Compared.
Further reading