Elapsed Time (Intro) — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. A movie ends at 4:00 and lasted 2 hours. It started at 2:00.
4:00 minus 2 hours gives a 2:00 start time.
2. A game ended at 5:30 after 1 hour. It started at 4:30.
5:30 minus 1 hour is 4:30.
3. Art class ended at 11:00 after 30 minutes. It started at 10:30.
11:00 minus 30 minutes is 10:30.
4. A nap ended at 3:15 after 45 minutes. It started at 2:30.
3:15 minus 45 minutes is 2:30.
5. Soccer practice ended at 6:00 after 90 minutes. It started at 4:30.
6:00 minus 1 hour 30 minutes is 4:30.
6. Lunch ended at 12:45 after 15 minutes. It started at 12:30.
12:45 minus 15 minutes is 12:30.
7. A walk ended at 8:00 after 1 hour. It started at 7:00.
8:00 minus 1 hour is 7:00.
8. Reading ended at 9:15 after 15 minutes. It started at 9:00.
9:15 minus 15 minutes is 9:00.
9. A drive ended at 2:45 after 2 hours. It started at 12:45.
2:45 minus 2 hours is 12:45.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Ends 7:00, lasted 1 hour
→ Started at 6:00
Started at 6:00
Ends 10:30, lasted 30 minutes
→ Started at 10:00
Started at 10:00
Ends 4:15, lasted 15 minutes
→ Started at 4:00
Started at 4:00
Ends 5:00, lasted 2 hours
→ Started at 3:00
Started at 3:00
Working backward from end time teaches students to reverse elapsed time problems.