Some people believe that crossing their middle finger over their index finger brings them good luck. In language, if someone says "fingers crossed" it means they hope everything goes smoothly.

Some people cross their fingers for good luck. Others do it to ward off bad luck. It is used both ways. Example: "I go into surgery now. Cross your fingers and wish me luck."

A lot of kids do this in school.

When people cross their fingers, they are hoping that will help them achieve what they wish for. They are hoping it will bring them luck in making their dreams come true.