Sa'd bin Abi Waqqas (RA) said that the Messenger of Allah (ﷺ) struck his hand against the other and (then with the gesture of his two hands) said: The month is thus, thus (two times). He then withdrew (one of) his fingers at the third turn.
Muhammad bin Sa'd reported on the authority of his father (Sa'd bin Abi Waqqas (RA) that the Apostle of Allah (ﷺ) had said: The month is thus and thus, and thus, i. e. ten, ten and nine.