[ Arithmetic. Mental calculation, etc.]

$[\quad$ Invariants $]$

The rabbits are sawing the log again, but now both ends of the log are secured. Ten middle pieces fell, while the two end pieces remained secured. How many cuts did the rabbits make?
How many logs did the hares receive

## Solution

The hares received 12 logs - 10 fallen and 2 secured. Therefore, there were 11 cuts.

## Answer

The problem