Tricky tasks to exercise your brain

Worker’s salary

A farmer hired a worker to build a water well. He promised to pay him with gold every day. The worker said that it would take him 7 days and he would start on Monday. The farmer had a gold bar and he planned to saw 1/7 of the bar every day. However, when he looked at the tool he wanted to use for sawing, he realized that he could only make two cuts. What should he do to not break the deal?