K-5 friendly lesson
One small step at a time.Read the idea, try the activity, and celebrate each win as you go.

Rounding puzzles

Welcome to Rounding Escape Room. Use clues to figure out mystery numbers by thinking backward from rounded results.

Do this: Read the concept below, then try the quiz or activity.

Lesson 12 of 202

Concept

In a rounding puzzle, you know the rounded answer and must find numbers that fit.

šŸ•µļø Puzzle Thinking: If a number rounds to 5,000 (nearest thousand), then the original number must be between: - 4,500 and 5,499

Why? - 4,500 is the first number that rounds up to 5,000 - 5,499 is the last number that still rounds down to 5,000

šŸŽÆ Another one: Rounds to 320 (nearest ten) means the number is from 315 to 324.

🌟 Rounding puzzles build flexible thinking: - forward rounding - backward reasoning - checking boundaries

Try it

Solve the puzzle clues.

1. I round to 8,000 to the nearest thousand. My hundreds digit is 7. Name one possible number. 2. I round to 46,000 to the nearest thousand. What is the smallest possible number? 3. I round to 46,000 to the nearest thousand. What is the largest possible number? 4. I round to 590 to the nearest ten. Give two possible numbers. 5. I round to 300,000 to the nearest hundred thousand and I am less than 250,000. What is one possibility?

šŸ† Challenge: 6. Find all whole numbers that round to 120 (nearest ten).