Round and Round Again
The purpose of this lesson is for students to use their understanding of rounding to consider all the numbers that round to a given number.
Students deepen their understanding of rounding to go beyond accurately rounding individual numbers as they think about what numbers round to a given number. Working backward from a multiple of 10 or 100 allows students to think about the relative distance of numbers and the range of numbers that round to the given multiple of 10 or 100. Students then use this understanding to write clues to help their classmates guess a mystery number. What a number rounds to becomes a useful way to describe a number in this game.
- Action and Expression
- Recognize and generalize patterns in the rounding of whole numbers within 1,000.
Let’s look for patterns in rounding.
Materials to Gather
- Each student needs an index card.
|Activity 1||15 min|
|Activity 2||20 min|
|Lesson Synthesis||10 min|
Teacher Reflection Questions
What was the best question you asked students today? Why would you consider it the best one based on what students said or did?
- Target Numbers (1–5), Stage 7: Subtract Hundreds, Tens, or Ones (Addressing)
- How Close? (1–5), Stage 4: Add to 1,000 (Addressing)
- Capture Squares (1–3), Stage 6: Multiply with 1–5 (Supporting)