Numbers All A-Round
Students will be able to round up with seven-digit whole numbers.
- Use a video projector to show the "Rounding Numbers Song" by Numberock.
- Tell students that today we are going to round numbers to the nearest hundred thousand.
Explicit Instruction/Teacher modeling(10 minutes)
- Review the definition of rounding (making a number simpler but keeping its value close to what it was) and the purpose of rounding (giving a less specific or approximate amount that is is easier to think about or count).
- Write a four-digit number on the board (like 4,731) and explain that you are going to round to the nearest thousand. Underline the digit in the thousands place (this is the place value that you are rounding to).
- Remind students that the digit to the right of the underlined digit will tell you whether you should round up or down. Circle the digit to the right of the underlined digit (this is the digit that determines how to round the number).
- Explain that if the digit is five or more, you should round up and if the digit is less than five, you should round down.
- Draw or display a number line from one to 10 to illustrate the fact that the numbers five and up are closer to 10, while the numbers less than five are closer to one. Draw an arrow from five to ten and another arrow, pointing the opposite way, from four to one.
- Round the number you've written on the board and remind students that when rounding up, the underlined digit increases by one and all digits to the right become zero. If rounding down, the underlined digit remains the same, while all digits to the right become zero.
- Give another example with a six-digit number. With this example, use a number that you will round down, like 820,143.
Guided Practice(10 minutes)
- Hand out the Round 'Em Up and Down worksheet. Review examples A and B, then solve the first problem with the class as another example.
- Have students complete the rest of the worksheet with a partner.
Independent working time(10 minutes)
- Hand out the Rounding Around Town worksheet and have students complete it independently.
- Circulate and offer support as needed. Go over the worksheet with the class when finished.
- Have students review rounding with smaller (two or three digit) numbers.
- Have students use number lines as they round to support their understanding.
- Provide additional examples during guided practice.
- Have students round a single number to multiple place values (i.e., round 239,481 to the nearest tenth, hundred, thousand, ten thousand, and hundred thousand).
- Have students apply the skills learned to solve addition word problems (i.e., if Gio has 2,319 collectible cards and Ken has 915,827, about how many do they have altogether?).
- Use an online number generator to come up with unique numbers for each student. Print or write each number on a slip of paper and underline one digit.
- Hand out the numbers to students and instruct them to round their number to the underlined place value.
- Collect as an exit card.
Review and closing(5 minutes)
- Using number magnets (or sticky notes labeled with single digits) create a random six-digit number on the board.
- Invite students up to the board to round the number to the nearest thousand, ten thousand, or hundred thousand by changing the digits with new magnets (or sticky notes).
- Repeat with several numbers.