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Worksheet Grade 3 Math

Pebble Lane's Storm Drain Route: A Grade 3 Elapsed Time Worksheet

Students read a fictional storm crew's morning log of start and stop times, then find how many minutes the crew spent at each catch basin and on the whole route.

Objectives

  1. Students will find how many minutes passed between a start time and a stop time.
  2. Students will add and subtract time intervals given in minutes.
  3. Students will compare six time intervals and tell which one is longest.

Vocabulary

Catch basin
A catch basin is a storm drain inlet with a sump underneath that traps sediment, leaves, and trash before water flows on into the storm sewer pipe. Crews periodically clean out catch basins so they do not clog or send debris downstream.
Storm drain
A storm drain is the grate at the edge of a street that swallows rainwater and sends it through pipes to the nearest creek or river. That water is usually not treated, so only rain belongs down the drain.

Also: time interval, minute

Teacher overview

Pebble Lane is a fictional town whose storm crew clears leaves out of catch basins after a heavy rain, and the crew logs the time it starts and stops at every basin. Those paired times give a clean set of elapsed-time problems in minutes, all inside one morning. The error to watch for is subtracting the two minute numbers as if they stood alone, which turns the stretch from 9:52 a.m. to 10:10 a.m. into 42 minutes instead of 18 minutes. Items 3 and 11 cross the hour on purpose so that mistake shows up in student work where it can be corrected.

Pebble Lane's Storm Drain Route: A Grade 3 Elapsed Time Worksheet — Grade 3 Math
Name: ____________________________ Date: ______________

Student Worksheet

A storm crew works in the town of Pebble Lane. The crew clears leaves out of catch basins after a big rain. A basin is the grate in the street that takes rainwater away. Here is the crew's log for one morning.

Basin Start time Stop time
Basin 1 9:05 a.m. 9:20 a.m.
Basin 2 9:25 a.m. 9:47 a.m.
Basin 3 9:52 a.m. 10:10 a.m.
Basin 4 10:15 a.m. 10:45 a.m.
Basin 5 10:50 a.m. 11:14 a.m.
Basin 6 11:20 a.m. 11:32 a.m.
  1. How many minutes did the crew work at Basin 1?
  2. How many minutes did the crew work at Basin 2?
  3. How many minutes did the crew work at Basin 3?
  4. How many minutes did the crew work at Basin 4?
  5. How many minutes did the crew work at Basin 5?
  6. How many minutes did the crew work at Basin 6?
  7. Which basin took the crew the most time?
  8. How many more minutes did Basin 4 take than Basin 6?
  9. The crew left Basin 2 at 9:47 a.m. It got to Basin 3 at 9:52 a.m. How long was the drive?
  10. Add the work times for Basin 1, Basin 2, and Basin 3. How many minutes is that?
  11. The crew began at Basin 1 at 9:05 a.m. It finished at Basin 6 at 11:32 a.m. How many minutes was the whole route?
  12. The crew plans on 20 minutes for each basin. Look at your answers for items 1 through 6. At how many basins did the crew work more than 20 minutes?
  13. Basin 4 was packed with wet leaves. Tell why a packed basin takes more time than a clear one.

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: 15 minutes. From 9:05 a.m. to 9:20 a.m. is 15 minutes, because 5 + 15 = 20.
  2. Answer: 22 minutes. From 9:25 a.m. to 9:47 a.m. is 22 minutes, because 47 − 25 = 22.
  3. Answer: 18 minutes. From 9:52 a.m. to 10:00 a.m. is 8 minutes, and 10:00 a.m. to 10:10 a.m. is 10 more, so 8 + 10 = 18 minutes. A student who writes 42 subtracted 10 from 52 without crossing the hour.
  4. Answer: 30 minutes. From 10:15 a.m. to 10:45 a.m. is 30 minutes, because 45 − 15 = 30.
  5. Answer: 24 minutes. From 10:50 a.m. to 11:00 a.m. is 10 minutes, and 11:00 a.m. to 11:14 a.m. is 14 more, so 10 + 14 = 24 minutes.
  6. Answer: 12 minutes. From 11:20 a.m. to 11:32 a.m. is 12 minutes, because 32 − 20 = 12.
  7. Answer: Basin 4. It took 30 minutes, which is longer than 15, 22, 18, 24, and 12 minutes.
  8. Answer: 18 minutes. Basin 4 took 30 minutes and Basin 6 took 12 minutes, so 30 − 12 = 18 minutes.
  9. Answer: 5 minutes. From 9:47 a.m. to 9:52 a.m. is 5 minutes, because 52 − 47 = 5.
  10. Answer: 55 minutes. Add the first three work times: 15 + 22 = 37, and 37 + 18 = 55 minutes.
  11. Answer: 147 minutes. From 9:05 a.m. to 11:05 a.m. is 2 hours, which is 120 minutes. From 11:05 a.m. to 11:32 a.m. is 27 more minutes, so 120 + 27 = 147 minutes.
  12. Answer: 3 basins. Basin 2 took 22 minutes, Basin 4 took 30 minutes, and Basin 5 took 24 minutes. Each of those is more than 20 minutes, and 15, 18, and 12 minutes are not.
  13. Answer: The crew has to lift out more leaves before the water can drain, so the work takes longer. Accept any answer that ties the extra minutes to the extra leaves the crew must remove.

Differentiation

Support

Give students a printed clock face or an open number line for each item so they can hop from the start time to the next hour and then to the stop time. Work item 1 and item 3 together as a class, since item 3 is the first one that crosses an hour. Allow students to skip item 11 and answer it last with a partner.

Extension

Ask students to plan a seventh stop that keeps the crew's whole route under 160 minutes, stating the start time, the stop time, and the drive time from Basin 6. Have them show the arithmetic that proves the route still fits, then write one sentence explaining which stop they would shorten if the crew fell behind.

ELL supports

Pre-teach "catch basin," "start time," "stop time," and "drive" with a simple street drawing and a demonstration clock. Post the sentence frame "The crew worked ___ minutes at Basin ___." for items 1 through 6. Let students answer item 13 by pointing to a picture of a leaf-filled grate and adding two or three words with support.

Extensions

Have students time three short classroom routines to the minute, such as lining up, passing out journals, and cleaning the sink area. Ask them to record a start time and a stop time for each routine, find the elapsed minutes, and then compare their three intervals the same way they compared the crew's six basins.