Rounding Up to the Nearest Hundred
Students will be able to round a given number to the nearest hundred.
- Review rounding to the nearest ten at the beginning of this lesson.
- Tell the students that today they are going to learn how to round a number to the nearest hundred.
- Remind them that rounding is a way of estimating.
- Explain that when rounding to the nearest hundred, the tens place is of particular importance.
- Share the following rules with the students about rounding to the nearest hundred: If the digit in the tens place is between 0 and 4, round down to the nearest hundred. If the digit in the tens place is between 5 and 9, round up to the nearest hundred.
- Let the students know that the rules stand, regardless of the size of the number involved.
- Come up with a few numbers, such 274, 628, and 7,641, to model rounding to the nearest hundred.
Explicit Instruction/Teacher Modeling(10 minutes)
- Choose one of the numbers to round to the nearest hundred, such as 274, and write it on the board.
- Using base ten blocks, show two 100s, seven 10s, and four ones blocks. Also, show two hundreds blocks versus three hundreds blocks.
- Explain that in this case, the number would be rounded up because the tens place is seven.
Guided Practice/Interactive Modeling(15 minutes)
- Put the students in pairs, and pass out base ten blocks.
- Tell the students to pick up their supplies and write down the following numbers: 628 and 7,641.
- Ask them to use the strategy demonstrated previously to round the remaining numbers to the nearest hundred.
- After a few minutes, ask for volunteers to raise their hands and share the steps involved.
- As each number is rounded aloud by the class, write down the steps on the board.
- Give the students time to finish rounding the numbers given based on the strategy reviewed and the previous feedback given by the class.
- After each of the given numbers are rounded, review them with the class for accuracy.
Independent Working Time(15 minutes)
- Write 7-10 problems on the board for your students to solve with their blocks.
- Enrichment: Give your students more challenging numbers in value and complexity to round to the nearest hundred. Have your students complete the lesson without base ten blocks.
- Support: Observe and monitor your students more closely. Practice rounding to the nearest ten before working up to rounding to the nearest hundred. Use manipulatives to show the students visually how to determine the nearest hundred.
- Walk around and observe the students as they work on completing the assignment accurately.
Review and Closing(5 minutes)
- Ask for volunteers to share their answers and work.
- As the problems are reviewed in front of the class, have the students check their answers for accuracy.