There are no actual attendance requirements for members of United States Congress, which means a session operates no matter how many are present. Many Americans are troubled to discover that, to earn an annual salary that starts at $174,000, members of Congress are not even required to show up.
A total of 100 U.S. Senate members and 435 House of Representatives hold office in the U.S. Congress, and while there are rules governing the number of votes required to pass legislation, they are expressed in percentages rather than actual numbers. Most bills require only a simple majority to pass either house, which would be 218 of the 435 representatives, or 51 of the 100 senators. However, the rule applies only to those actually present at the session. As such, if only 80 senators were present during a vote, only 41 votes would be required to for it to pass.