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Lesson plan Grade 4 Math

Wexford Well Field Report: Rounding Big Gallon Totals

A 40-minute grade 4 lesson where students round a fictional well field's large gallon totals to the nearest ten, hundred, and thousand for a monthly report.

Objectives

  1. Students will round multi-digit whole numbers to the nearest ten, hundred, and thousand.
  2. Students will use rounding to estimate a combined total for a report.

Vocabulary

Aquifer
An aquifer is an underground layer of rock, sand, or gravel that holds water in the tiny spaces between its grains. Wells reach down into aquifers to bring water up to the surface.

Also: round, estimate, well

Teacher overview

The fictional town of Wexford pumps its drinking water from wells that reach an aquifer underground, and each month the town writes a report of how much water each well pumped. Exact gallon counts are long and hard to compare, so the report rounds them. This lesson uses that real purpose to practice rounding multi-digit numbers to the nearest ten, hundred, and thousand, the skill in 4.NBT.A.3. A common misconception is that a deciding digit of 5 always rounds down; the lesson stresses that a deciding digit of 5 or more rounds up.

Procedure

Hook (5 min): Write 5,472 on the board and ask why a town report might not want to print that exact number every month. Draw out that a rounded number is easier to read and compare. Tell students that Wexford rounds its well numbers for the same reason.

Direct instruction (10 min): Model rounding 5,472 to the nearest hundred without using handout numbers. Underline the hundreds digit 4, look at the next digit 7, and because 7 is 5 or more, round up to 5,500. Then round the same number to the nearest thousand, showing it becomes 5,000 because the hundreds digit 4 is less than 5. Label each step.

Guided practice (10 min): As a class, round 27,643 to the nearest ten, then the nearest hundred, then the nearest thousand, using a place-value chart. Pause on the nearest hundred so students see the tens digit 4 sends it down to 27,600. Ask a check question: does 27,643 round to 27,600 or 27,700 at the hundreds place, and why?

Independent practice (10 min): Students complete problems 1 through 6 on the Student Handout. Circulate to check that each student underlines the rounding digit and looks at the digit to its right before deciding.

Closure and exit ticket (5 min): Students answer handout problem 7 and hand it in. A student who writes 8,500 has rounded to the nearest hundred correctly. Reteach the place-value step the next day if many students miss it.

Wexford Well Field Report: Rounding Big Gallon Totals — Grade 4 Math
Name: ____________________________ Date: ______________

Student Handout

Wexford writes a water report each month. Round each well total as asked. Underline the rounding digit first.

  1. Well A pumped 3,468 gallons. Round it to the nearest hundred.
  2. Well A pumped 3,468 gallons. Round it to the nearest thousand.
  3. Well B pumped 12,748 gallons. Round it to the nearest ten.
  4. Well B pumped 12,748 gallons. Round it to the nearest hundred.
  5. Well B pumped 12,748 gallons. Round it to the nearest thousand.
  6. Two wells pumped 3,468 and 12,748 gallons. Round each to the nearest thousand, then add to estimate the total.
  7. A report rounds 8,529 gallons to the nearest hundred. What number does it print?

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: 3,500 gallons. The hundreds digit is 4, and the next digit 6 is 5 or more, so round up to 3,500.
  2. Answer: 3,000 gallons. The thousands digit is 3, and the next digit 4 is less than 5, so round down to 3,000.
  3. Answer: 12,750 gallons. The tens digit is 4, and the next digit 8 is 5 or more, so round up to 12,750.
  4. Answer: 12,700 gallons. The hundreds digit is 7, and the next digit 4 is less than 5, so round down to 12,700.
  5. Answer: 13,000 gallons. The thousands digit is 2, and the next digit 7 is 5 or more, so round up to 13,000.
  6. Answer: 16,000 gallons. 3,468 rounds to 3,000 and 12,748 rounds to 13,000, and 3,000 + 13,000 = 16,000.
  7. Answer: 8,500 gallons. The hundreds digit is 5, and the next digit 2 is less than 5, so the number stays 8,500.

Differentiation

Support

Give students a place-value chart where they can write one digit per box, and a rule strip: "5 or more, round up; 4 or less, round down." Start with rounding to the nearest thousand, where only the leading digits change, before the nearest ten.

Extension

Ask students to find a number that rounds to 4,000 at the nearest thousand but to 3,500 at the nearest hundred, and to explain why both can be true for the same number.

ELL supports

Pre-teach "round," "nearest," and "estimate" with a number line that shows a value sliding to the closer benchmark. Provide a sentence frame: "The rounding digit is ___, the next digit is ___, so I round ___."