Water for Schools
Menu

Worksheet Grade 2 Math

Duskford's Water Walk: A Grade 2 Estimating Lengths Worksheet

A class walks past a hydrant, a meter lid, and a storm grate carrying no ruler, and students pick the sensible estimate and the right unit for each part.

Objectives

  1. Students will estimate a length in inches or feet by comparing an object with a stated benchmark.
  2. Students will choose the measuring tool that fits the size of the object.
  3. Students will explain why a smaller unit gives a larger number for the same object.

Vocabulary

Water meter
A device that measures how much water a home or business uses so the utility can bill fairly. Reading the meter can also reveal hidden leaks.

Also: estimate, unit, hydrant, measuring tape

Teacher overview

Most of a water system is buried, yet a few parts of it sit in plain view along a sidewalk, including a drinking fountain spout, a fire hydrant, the lid over a water meter, and a storm grate at the curb. This worksheet walks a class from the town of Duskford past those parts with no ruler in hand, so each length has to be judged against four lengths the class already knows. Nothing here is measured and only item 4 adds, which keeps the whole page on the question of whether an estimate and its unit are sensible. The misconception the items are built to catch is the belief that the larger number names the longer length even when the units differ, so 100 centimeters gets called longer than 7 feet. A student who makes that call on item 10 should stand a meter stick beside the classroom door and answer again.

Duskford's Water Walk: A Grade 2 Estimating Lengths Worksheet — Grade 2 Math
Name: ____________________________ Date: ______________

Student Worksheet

A class in the town of Duskford took a walk to find water system parts it could see. The class did not bring a ruler. Instead the class used four lengths it already knew.

  • A new pencil is about 7 inches long.
  • The teacher's desk is about 3 feet tall.
  • The classroom door is about 7 feet tall.
  • A meter stick is 1 meter long. That is 100 centimeters, and it stands about as tall as the desk.

Use these four lengths. Write a number and a unit in each answer.

  1. The drinking fountain spout is about as long as one new pencil. About how long is the spout?
  2. The fire hydrant is about as tall as the teacher's desk. About how tall is the hydrant?
  3. Sam says the hydrant is about 3 inches tall. Is Sam right? Tell how you know.
  4. The storm grate is as wide as three new pencils in a row. About how wide is the grate?
  5. The crew must measure a pipe that is longer than the classroom door. Should the crew use a 12-inch ruler or a 25-foot tape? Tell why.
  6. The crew must measure the dial on the water meter. That dial is smaller than a pencil. Should the crew use a 12-inch ruler or a 25-foot tape? Tell why.
  7. One new pipe on the crew's truck is much longer than the classroom door is tall. Is that pipe about 20 inches long or about 20 feet long?
  8. A water bottle by the fountain is a little taller than a new pencil. Is the bottle about 20 centimeters tall or about 20 meters tall?
  9. The crew measured the pipe from item 7 two times. The first time was in feet. The second time was in inches. One answer was 20 and the other was 240. Which answer was in inches?
  10. Mia says the meter stick is longer than the classroom door, because 100 is more than 7. Is Mia right? Tell how you know.

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: 7 inches. The spout matches one new pencil, and the pencil is 7 inches long.
  2. Answer: 3 feet. The hydrant matches the teacher's desk, and the desk is 3 feet tall.
  3. Answer: No. Three inches is much shorter than one pencil, while the hydrant is as tall as the desk, so the estimate needs feet rather than inches. Accept any answer that names the desk or the pencil as the reason.
  4. Answer: 21 inches. Three pencils in a row give 7 + 7 + 7 = 21 inches.
  5. Answer: The 25-foot tape. The pipe is longer than the 7-foot door, so a 12-inch ruler would have to be laid down and marked many times, while the tape reaches the whole pipe at once.
  6. Answer: The 12-inch ruler. The dial is smaller than a 7-inch pencil, so the ruler covers it in one placement, and a 25-foot tape is far longer than the object being measured.
  7. Answer: 20 feet. Twenty inches is close to the 21-inch grate in item 4, and the 7-foot door is much taller than that grate, so only 20 feet can describe a pipe much longer than the door is tall.
  8. Answer: 20 centimeters. A meter stick holds 100 centimeters and stands about as tall as the desk, so 20 centimeters is a short length that suits a bottle, while 20 meters would be 20 meter sticks laid end to end.
  9. Answer: 240 inches. An inch is shorter than a foot, so it takes more inches than feet to cover the same pipe, and the larger number therefore belongs to the smaller unit.
  10. Answer: No. The meter stick stands about as tall as the desk, and the door is taller than the desk, so the door is longer. The number 100 is larger only because a centimeter is a small unit. Accept any answer that compares the meter stick with the desk.

Differentiation

Support

Hand these students a real pencil, a 12-inch ruler, and a meter stick to hold while they work, and start them at items 1, 2, and 4, where the object is matched to a benchmark they can pick up. Before item 8, set a water bottle beside the pencil on the desk so the walk in the town of Duskford is acted out rather than pictured. Students who still miss items 9 and 10 should line the meter stick up against the door frame and mark the gap with tape.

Extension

Ask students to write two more walk items for the town of Duskford, each naming one object, one benchmark, and two choices of which only one is sensible, then to trade papers and answer a partner's items. Require the writer to name the benchmark that settles each item, because an item with no benchmark has no single defensible answer.

ELL supports

Post the four benchmark lengths as labeled photographs, with the pencil, the desk, the door, and the meter stick shown together, and keep them in view for the whole worksheet. Preteach the four unit words by holding up the object each one names, and say the plural forms aloud. Post the sentence frames "The ___ is about ___ inches" and "The ___ is about ___ feet," and read items 3, 5, 6, and 10 aloud, since those four ask for an explanation rather than a length. Name the town of Duskford as a made-up place before students begin, so the setting is not mistaken for somewhere they should already know.

Extensions

Take the class on the same walk at your own school, list five water system parts that can be seen from the sidewalk, and have students sort that list into parts measured in inches and parts measured in feet. Comparing the class list with the one from the town of Duskford shows that the unit follows the size of the object rather than the kind of object it is. A second round can ask which parts would need a measuring tape and which would need a ruler, which returns the tool question of items 5 and 6 to objects the students chose themselves.