Let’s say a validator has 10,000 total SAFE staked and you have delegated 5,000 of it. This means you have a 50% share in this validator. The person running the validator sets the commission fee to 10%. Let’s imagine a validator received 200 SAFE in staking rewards. Since you have a 50% stake, you get a 50% share of the rewards (100 SAFE) minus the 10% commission (10 SAFE), so you end up with 90 SAFE. (200x.5x.90)