Mindbender

A: Tony shook his head. "One pound?" he said. "I haven t got that much."

"Well, you can surely spare something," Gwen pleaded. "How much do you have?"

"I'll lend you 50p if you can figure it out," her brother replied. "It's a penny less than nine times what its digits add up to."

So how much did he have?

B: "Did you ever notice something special about those old peso notes of yours?" Alan asked. "I mean, their 8-digit serial numbers."

Mike smiled. "Certainly, and that's partly why I keep them," he replied. "They re both perfect squares, and each has its first half just one more than its second half."

Quite a coincidence, but be careful! What were those truly odd serial numbers?