# Gallery Problems Exercise

## A Number Trick

**Work Time**

# A Number Trick

- Work with a partner. Give each of these directions to your partner, one at a time:
- Write down a number, but don’t let me see which number you wrote.
- Add 3 to your number.
- Multiply that sum by 5.
- Subtract 10 from that product.
- Divide that difference by 5.
- Subtract your original number from the quotient.
- The difference is 1. Am I correct?

- Use what you know about simplifying expressions to show why the trick works.
- Make up your own number trick. Try it with your partner.