1. "Did you make a note of the serial number?" asked Lucy. Rob smiled. "Of course, and it's a funny one," he replied. "If you subtract the first part of it from the square of the last four figures, you get it again. So 120 from the square of 1096 makes 1201096." Can you find the 8-digit number that works that way with its last four digits?

24486189

56891074

79308906