A good example to intuitively understand the concept:
Say you have 100 dollars to buy 5 things.
You can buy whatever you want for the first 4 things as long as there’s money left. But for the fifth thing, the amount of money you can spend is restricted at the moment you bought the fourth thing. You cannot choose whatever you want anymore.
In this case, the degree of freedom is 4, because you can freely choose the first 4 things.
