1. Stan rushed into the study, waving a sheet of paper. “I got something, Dad,” he cried. “Look.” Keith looked. “The number I gave you yesterday?” he asked. “What did you discover about it?” “Something interesting,” the boy replied. “If you put its second half in front of its other four digits, you get three less than seven times the number.” He was right, so what was the number?

The number was 45107992

The number was 10417292

The number was 23218856