“Today we solved lots of number riddles. I’m really stumped on this one and need your help.“

Display the chart with only the first clue showing. “My number has more than 6 tens.“

“What could my secret number be?” (70, 75, 89, 91, any number from 70 to 120)

Display the second clue: “My number is less than 100.”

“Now what do you know about the secret number?” (We can cross out any of the numbers that are over 100.)

Display the third clue: “My number has 8 tens.”

“How does this clue change what my secret number could be?” (Now we know we can cross off all the numbers that don’t have 8 tens.)

“What could my number be now?” (80–89)

Display the last clue: “My number is the sum of .”

“What is my secret number? Explain your thinking.”