Home > CC3MN > Chapter 3 > Lesson 3.1.1 > Problem3-5

3-5.

At the fair, Kate found a strange machine with a sign on it labeled, “Enter a number.” When she pushed the number $15$, the machine displayed $9$. When she entered $23$, the machine displayed $17$. Perplexed, she tried $100$, and the machine displayed $94$

1. What is the machine doing?

Find a pattern.

$15→9$
$23→17$
$100→94$

For every number entered into the machine, it subtracts $6$.

2. What would the machine display if she entered $77$?

Use the pattern you found in part (a).