(harder version)

We certainly had some excitement around here last week. It all started when Danny and Barney were visiting last weekend. They were riding their bikes when Barney fell and hurt his hand, so we went to the emergency room to check it out. Sure enough, he had a broken finger! After X-rays and a taped up finger, Barney seemed hardly the worse for wear, so we decided to stop by the local ice cream store on the way home.
 

"Does it hurt much?" asked Danny in a worried tone.

"Only when I forget and try to bend it," answered his brother. "I'm glad it's my left hand too, so I can still write."

"What are you thinking about writing at a time like this?" I asked, taking a bite out of my sugar cone.
 

"Oh, I was thinking of writing Gina. She's on vacation and it will be exciting to tell her about my broken finger – especially if I make up a math challenge about it," said Barney, laughing.

I had to admit that this was true. His cousin, Gina just loves math challenges. "As soon as we get home, I'll get some paper and a pen for you. Do you have an idea already?" I asked.

"Yes, in fact I do," said Barney, smiling a bit. "I was listening to the doctor as she was taping up my finger and I got an idea for it."

Here is what Barney wrote to his cousin:
 

"What would you write back to Barney? I hope you will tell him how you figured out your answer."

Love,
Aunty Math