How many times do you need to regroup to subtract 316 from 624?

To subtract 316 from 624, you need to regroup twice. Start by subtracting 6 from 4 in the ones place, which requires regrouping from the tens place. Then, subtract 1 from 2 in the tens place, which also requires regrouping from the hundreds place. Finally, subtract 3 from 5 in the hundreds place to get the final result of 308.