Worksheet Grade 4 Health & Consumer Science
The Velasco Family Well Test Report: Rounding the Numbers
A grade 4 worksheet in which students round the results on a fictional private-well lab report to build the family's yearly summary card.
Objectives
- Students will round multi-digit test results to a named place value.
- Students will compare two rounded results and find the difference between them.
- Students will explain why a family rounds lab numbers before recording them.
Vocabulary
Key words: private well, lab report, round, place value
Teacher overview
Households on a private well pay for their own water testing and keep their own records, so reading a lab report is a genuine consumer task rather than a school exercise. This worksheet gives the fictional Velasco family a one-page report and asks students to round each result for the summary card the family keeps year to year. Rounding is the right operation here for a reason worth naming aloud: the family is not trying to change the measurement, only to compare this year with last year at a glance. Expect two errors: rounding to the wrong place because students read the place name too quickly, and rounding a number ending in 5 downward. Item 5 is the one that exposes the second habit.
Student Worksheet
Imagine the Velasco family. They live outside the town of Arrowdale and get their water from a private well in the side yard. Once a year they mail a water sample to a lab. Here is the report the lab sent back.
| Test | Exact result |
|---|---|
| Hardness | 148 mg/L |
| Total dissolved solids | 386 mg/L |
| Sodium | 27 mg/L |
| Chloride | 62 mg/L |
| Depth of the well | 165 feet |
| Gallons the pump moved last year | 47,350 gallons |
| pH | 7.4 |
The Velascos copy the results onto a summary card. On the card they round each number so it is easier to compare one year with the next.
- Round the hardness result, 148 mg/L, to the nearest ten.
- Round the total dissolved solids result, 386 mg/L, to the nearest hundred.
- Round the sodium result, 27 mg/L, to the nearest ten.
- Round the chloride result, 62 mg/L, to the nearest ten.
- Round the depth of the well, 165 feet, to the nearest ten feet.
- Round the gallons the pump moved last year, 47,350 gallons, to the nearest thousand.
- Round the same number, 47,350 gallons, to the nearest ten thousand.
- EPA suggests that drinking water stay in a pH range of 6.5 to 8.5. The Velascos' pH result was 7.4. Is their result inside that range?
- Use your rounded answers from questions 3 and 4. How many more mg/L is the rounded chloride result than the rounded sodium result?
- Explain in one or two sentences why the Velascos round the lab numbers before writing them on the summary card.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
- Answer: 150 mg/L.
The digit in the ones place is 8, which is 5 or more, so the tens digit goes up from 4 to 5 and 148 rounds to 150. - Answer: 400 mg/L.
The digit in the tens place is 8, so the hundreds digit goes up from 3 to 4 and 386 rounds to 400. - Answer: 30 mg/L.
The ones digit is 7, so 27 rounds up to 30. - Answer: 60 mg/L.
The ones digit is 2, which is less than 5, so 62 rounds down to 60. - Answer: 170 feet.
The ones digit is 5, so the tens digit goes up from 6 to 7 and 165 rounds to 170. A student who answers 160 rounded a 5 downward. - Answer: 47,000 gallons.
The hundreds digit is 3, which is less than 5, so the thousands digit stays at 7 and the number rounds down to 47,000. - Answer: 50,000 gallons.
The thousands digit is 7, which is 5 or more, so the ten thousands digit goes up from 4 to 5 and the number rounds to 50,000. - Answer: Yes.
The result 7.4 falls between 6.5 and 8.5, so it sits inside the suggested range. - Answer: 30 mg/L.
The rounded chloride result is 60 and the rounded sodium result is 30, and 60 - 30 = 30 mg/L. - Answer: Rounded numbers are easier to compare from one year to the next.
Any answer earns credit if it says rounding makes the numbers simpler to read, remember, or line up beside last year's card, rather than saying rounding makes the test more accurate.
Differentiation
Support
Give students a place-value chart with the columns labeled and a highlighter, and have them highlight the digit in the place they are rounding to before they touch the number. Work item 1 aloud with the chart in front of the class, and provide a short number line marked in tens for items 1, 3, 4, and 5 so students can see which ten the value sits closer to.
Extension
Suppose next year's report shows a hardness result of 152 mg/L and a pump total of 52,600 gallons. Ask students to round both new numbers to the same places used on the card, then to write two sentences comparing the new card with the one they just built.
ELL supports
Pre-teach "round," "nearest," "lab report," and "well" with a labeled sketch of a house, a well, and an envelope going to a lab. Provide a sentence frame for item 10: "The family rounds the numbers because ___." Allow students to say each rounded answer aloud to a partner before writing it, and accept the digits alone for items 1 through 7 if the unit is written once at the top of the column.
Extensions
Ask students to design the summary card itself on an index card: a title, a row for each test, a column for this year, and a column for next year. Suppose the family adds one more test next year, such as iron. Students should leave a blank row for it and explain in one sentence why a card with room to grow is more useful than a card that is exactly full.