Time and Elapsed Time

Grade 4 · Math · Study Guide

Learn to read clocks and calculate how much time has passed between two events.

Reading time on a clock is a skill you use every single day. An analog clock has a short hour hand and a long minute hand. The minute hand moves all the way around the clock in 60 minutes (1 hour). Each number on the clock represents 5 minutes, so when the minute hand points to 3, it means 15 minutes have passed.

Elapsed time is the amount of time that passes from a start time to an end time. To find elapsed time, count forward from the start time to the end time. For example: a movie starts at 2:15 PM and ends at 4:45 PM. From 2:15 to 4:15 is 2 hours. From 4:15 to 4:45 is 30 more minutes. Total elapsed time: 2 hours and 30 minutes.

A number line (also called a timeline) is one of the best tools for elapsed time. Mark your start time, then jump by hours and then minutes until you reach the end time. Count all your jumps at the end.

AM and PM are also important: AM is the time from midnight to noon, and PM is from noon to midnight. 12:00 AM is midnight, and 12:00 PM is noon.

Key terms

Elapsed time

The amount of time that passes between a start time and an end time.

AM

The hours from midnight (12:00 AM) to just before noon — morning time.

PM

The hours from noon (12:00 PM) to just before midnight — afternoon and evening.

Analog clock

A clock with hands that rotate around a face with numbers 1–12.

Flashcards

Elapsed time

How much time passes from start to end. Count forward on a number line.

AM

Morning hours from midnight to noon.

PM

Afternoon/evening hours from noon to midnight.

Minutes in 1 hour

60 minutes

Hours in 1 day

24 hours

2:15 PM to 4:45 PM = ?

2 hours and 30 minutes

Practice questions

1. A show starts at 3:30 PM and ends at 5:00 PM. How long is the show?

   1. 1 hour
   2. 1 hour 30 minutes
   3. 2 hours
   4. 2 hours 30 minutes
   Show answer

   Answer: 1 hour 30 minutes

   From 3:30 to 5:00: 3:30→4:30 is 1 hour, then 4:30→5:00 is 30 minutes. Total: 1 hr 30 min.

2. AM refers to the time between noon and midnight.

   Show answer

   Answer: False

   AM is the time from midnight to just before noon. PM is noon to midnight.

3. There are ___ minutes in one hour.

   Show answer

   Answer: 60

   There are 60 minutes in one hour. The minute hand makes one full rotation per hour.

4. School starts at 8:15 AM and ends at 3:15 PM. How long is the school day?

   1. 6 hours
   2. 7 hours
   3. 8 hours
   4. 9 hours
   Show answer

   Answer: 7 hours

   8:15 AM to 3:15 PM: count 8:15→9:15→10:15→11:15→12:15→1:15→2:15→3:15 = 7 hours.

5. If it is 10:45 AM and 30 minutes pass, the new time is ___.

   Show answer

   Answer: 11:15 AM

   10:45 + 30 minutes: 10:45 → 11:00 is 15 minutes, then 15 more minutes = 11:15 AM.

Fun facts

• Before clocks existed, people used sundials, hourglasses, and candles to track time!
• A day has 86,400 seconds — most people never think about time that way, but computers do!

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