Grade 3 · Measurement & Data · MAT-03-MD-002
Solve Elapsed-Time Problems
Represent solve elapsed-time problems with words, symbols, diagrams, or models appropriate to Grade 3.
Learning objectives
What you should be able to do
- Represent solve elapsed-time problems with words, symbols, diagrams, or models appropriate to Grade 3.
- Solve problems involving solve elapsed-time problems accurately and explain why the method works.
- Check results for reasonableness using a second representation, inverse relationship, benchmark, or property when appropriate.
Prerequisite check
Make sure the foundation is ready.
Checks conceptual readiness before new Grade 3 reasoning.
Checks whether prior skills are available for use, not only recalled by name.
Learn
Build the idea from meaning, not memorization.
Meaning of Solve Elapsed-Time Problems
Elapsed time measures the duration between a start time and an end time.
A reliable reasoning strategy
Jump along a time line in convenient chunks—hours, tens of minutes, then remaining minutes—and add the jumps.
Representations that should agree
Addition finds an end time from a duration; subtraction or counting up finds the duration between times. A correct model, equation, verbal explanation, or diagram should preserve the same quantities and relationships.
How to check the result
Check whether the answer fits the quantities, units, and structure of the problem. Use a second representation or inverse relationship when available, and explain what would make an answer unreasonable.
Interactive math lab
Change it. See what stays true.
Number Line Explorer
Move along the number line.
4 is one less. 5 and 6 is one more.
- build a model
- change one quantity
- predict before calculating
- explain why the result changes
Worked examples
Twenty different ways to see the concept work.
An activity starts at 9:05 and lasts 22 minutes. When does it end?
Count forward 22 minutes to 9:27.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 10:10 and lasts 29 minutes. When does it end?
Count forward 29 minutes to 10:39.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 8:15 and lasts 36 minutes. When does it end?
Count forward 36 minutes to 8:51.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 9:20 and lasts 43 minutes. When does it end?
Count forward 43 minutes to 10:03.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 10:25 and lasts 50 minutes. When does it end?
Count forward 50 minutes to 11:15.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 8:00 and lasts 16 minutes. When does it end?
Count forward 16 minutes to 8:16.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 9:05 and lasts 23 minutes. When does it end?
Count forward 23 minutes to 9:28.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 10:10 and lasts 30 minutes. When does it end?
Count forward 30 minutes to 10:40.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 8:15 and lasts 37 minutes. When does it end?
Count forward 37 minutes to 8:52.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 9:20 and lasts 44 minutes. When does it end?
Count forward 44 minutes to 10:04.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 10:25 and lasts 51 minutes. When does it end?
Count forward 51 minutes to 11:16.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 8:00 and lasts 17 minutes. When does it end?
Count forward 17 minutes to 8:17.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 9:05 and lasts 24 minutes. When does it end?
Count forward 24 minutes to 9:29.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 10:10 and lasts 31 minutes. When does it end?
Count forward 31 minutes to 10:41.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 8:15 and lasts 38 minutes. When does it end?
Count forward 38 minutes to 8:53.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 9:20 and lasts 45 minutes. When does it end?
Count forward 45 minutes to 10:05.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 10:25 and lasts 52 minutes. When does it end?
Count forward 52 minutes to 11:17.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 8:00 and lasts 18 minutes. When does it end?
Count forward 18 minutes to 8:18.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 9:05 and lasts 25 minutes. When does it end?
Count forward 25 minutes to 9:30.Use time-line jumps while remembering that 60 minutes make an hour.
An activity starts at 10:10 and lasts 32 minutes. When does it end?
Count forward 32 minutes to 10:42.Use time-line jumps while remembering that 60 minutes make an hour.
Practice
Guided practice with hints
01An activity starts at 9:05 and lasts 27 minutes. When does it end?
Hint: Jump along a time line in convenient chunks—hours, tens of minutes, then remaining minutes—and add the jumps.
Answer: 9:32
02An activity starts at 10:10 and lasts 34 minutes. When does it end?
Hint: Jump along a time line in convenient chunks—hours, tens of minutes, then remaining minutes—and add the jumps.
Answer: 10:44
03An activity starts at 8:15 and lasts 41 minutes. When does it end?
Hint: Jump along a time line in convenient chunks—hours, tens of minutes, then remaining minutes—and add the jumps.
Answer: 8:56
04An activity starts at 9:20 and lasts 48 minutes. When does it end?
Hint: Jump along a time line in convenient chunks—hours, tens of minutes, then remaining minutes—and add the jumps.
Answer: 10:08
05An activity starts at 10:25 and lasts 55 minutes. When does it end?
Hint: Jump along a time line in convenient chunks—hours, tens of minutes, then remaining minutes—and add the jumps.
Answer: 11:20
06An activity starts at 8:00 and lasts 21 minutes. When does it end?
Hint: Jump along a time line in convenient chunks—hours, tens of minutes, then remaining minutes—and add the jumps.
Answer: 8:21
Practice
Independent practice
01An activity starts at 8:15 and lasts 44 minutes. When does it end?
Answer: 8:59
02An activity starts at 9:20 and lasts 51 minutes. When does it end?
Answer: 10:11
03An activity starts at 10:25 and lasts 17 minutes. When does it end?
Answer: 10:42
04An activity starts at 8:00 and lasts 24 minutes. When does it end?
Answer: 8:24
05An activity starts at 9:05 and lasts 31 minutes. When does it end?
Answer: 9:36
06An activity starts at 10:10 and lasts 38 minutes. When does it end?
Answer: 10:48
07An activity starts at 8:15 and lasts 45 minutes. When does it end?
Answer: 9:00
08An activity starts at 9:20 and lasts 52 minutes. When does it end?
Answer: 10:12
Common mistakes
Learn to catch the error, not just the answer.
Remember that 60 minutes make one hour and organize jumps around hour boundaries.
Reconnect the answer to solve elapsed-time problems and verify that the model, calculation, and label describe the same quantity.
Applications & challenge
Use the idea beyond a single exercise.
Applications
- Plan travel, lessons, cooking, and activities.
- Use solve elapsed-time problems to interpret or solve a Grade 3 situation with quantities, diagrams, measurements, or data.
Challenge problems
An activity starts at 10:25 and lasts 20 minutes. When does it end?
10:45
An activity starts at 8:00 and lasts 27 minutes. When does it end?
8:27
An activity starts at 9:05 and lasts 34 minutes. When does it end?
9:39
An activity starts at 10:10 and lasts 41 minutes. When does it end?
10:51
Flashcards
Retrieve it from memory.
Flashcards
Card 1 of 4
Game mode
Solve Elapsed-Time Problems Challenge
Solve and explain Grade 3 problems involving solve elapsed-time problems without relying on answer guessing.
Practice
Mastery check
01An activity starts at 9:05 and lasts 37 minutes. When does it end?
Answer: 9:42
02An activity starts at 10:10 and lasts 44 minutes. When does it end?
Answer: 10:54
03An activity starts at 8:15 and lasts 51 minutes. When does it end?
Answer: 9:06
04An activity starts at 9:20 and lasts 17 minutes. When does it end?
Answer: 9:37
05An activity starts at 10:25 and lasts 24 minutes. When does it end?
Answer: 10:49
06An activity starts at 8:00 and lasts 31 minutes. When does it end?
Answer: 8:31
07An activity starts at 9:05 and lasts 38 minutes. When does it end?
Answer: 9:43
08An activity starts at 10:10 and lasts 45 minutes. When does it end?
Answer: 10:55
Terminology
Words to know
- elapsed time
- The amount of time between two moments.
- duration
- How long an event lasts.
Continue learning
Connected concepts
Curriculum references
Standards and instructional references
California Common Core State Standards for Mathematics — Grade 3, 3.MD.1
Primary standards alignment for Solve Elapsed-Time Problems.2023 Mathematics Framework for California Public Schools
Instructional emphasis on reasoning, representations, problem solving, and equitable access.