Maria was playing a game with her brother. She said, “I’m thinking of a number. When you multiply my number by six and add seven, you get twenty-five. What is my number?”
Find Maria’s number.
How big do you expect her number to be? Can you think of a reasonable number to try?
Pick a reasonable number and try Maria's steps. Let's try
. If Maria multiplies this number ( ) by , she would get . Then, adding , she would get .
Can you think of a number that might work better? Try it!
is smaller than , let's choose a bigger number. Let's try . If Maria multiplies by , she would get . Adding , she would get . Since Maria gets by using this number, is the number she described.
We now know that Maria's number is
Explain how you figured out your answer to Maria’s number puzzle.
Can you describe with words the steps that you took to find Maria's number?