Is it permissible to move one's fingers to count the Rak'ahs when in doubt about their number?

There is no objection to counting the rak'ahs with fingers for someone who forgets often, as scholars have explicitly stated the permissibility of doing so to rectify the prayer. Some scholars believe that it is better to count with pebbles or date pits to avoid contradicting the manner of placing fingers during bowing (ruku') and prostration (sujud).