Examples:

• The thief knew his number was up when the police surrounded the building.
• When the boss discovered the missing money, Tom realized his number was up.
• The criminal knew his number was up after seeing police cars outside.
• If you keep breaking the rules, your number will be up sooner or later.
• The boxer felt his number was up when he could no longer stand in the final round.
• She thought her number was up when the teacher asked who cheated on the test.
• After years of avoiding taxes, his number was finally up.
• The spy understood that his number was up once his identity was revealed.
• The corrupt politician knew his number was up after the investigation began.
• I missed deadlines for weeks, so I knew my number was up at work.
• In the movie, the villain realized his number was up when the hero returned.