When moving to the next or previous card in the card set, we use the < and > buttons or swiping. But if we want to get to a certain card somewhere in the middle of the card set and if we have a lot of cards in the set, this way navigation becomes slow and inconvenient. Tapping too fast does not produce a reliable result, at least in the editing module.
The suggestion is to use tap and hold feature. When a user taps and holds the button, the display shows the current card, but the card number changes, maybe, 4 numbers per second? After reaching the maximum or the minimum, cycles and continues until the user releases the button. After that the appropriate card is displayed.
And also sometimes we may want to go to the first or the last card in the set directly. In this case we may use a double-tap on the appropriate < or > button in the editing or study module.