Sally and Anna took turns multiplying numbers. Sally picked the number four. Anna multiplied that by 4 to get 16. Sally multiplied that by 4 to get 64. Anna multiplied that by 4 to get 256.
After going back and forth several times, one of them got the number 1,048,576. Who came up with that number—Sally or Anna?
Answer
Anna came up with that number. Note that all of Anna’s numbers end in 6 and all of Sally’s numbers end in 4. That’s all you need to know!