Grade 2 · Time & Money · MAT-02-TIME-002
Understand A.M. and P.M.
Use a.m. and p.m. to distinguish times in a12-hour cycle.
Learning objectives
What you should be able to do
- Use a.m. and p.m. to distinguish times in a12-hour cycle.
- Match common daily activities to plausible a.m./p.m. times.
- Explain why the same clock reading can occur twice in one day.
Prerequisite check
Make sure the foundation is ready.
Checks time-reading before adding day-period labels.
Learn
Build the idea from meaning, not memorization.
A12-hour clock repeats
The clock numbers1 through12 occur twice each day. A.M. and p.m. distinguish the first and second12-hour portions.
A.M. covers midnight through before noon
Times after midnight and before12 noon use a.m. Examples include7:00 a.m. for breakfast and10:30 a.m. for a morning class.
P.M. covers noon through before midnight
Times after12 noon and before midnight use p.m. Examples include3:00 p.m. for afternoon and8:00 p.m. for evening.
Noon and midnight are boundary points
12:00 noon is commonly labeled12:00 p.m.;12:00 midnight is12:00 a.m. Using the words noon or midnight can reduce confusion.
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.
- place time
- choose am pm
- match routine
- cross noon midnight
Worked examples
Twenty different ways to see the concept work.
7:00 breakfast.
7:00 a.m.Morning.
2:00 afternoon class.
2:00 p.m.After noon.
8:30 evening.
8:30 p.m.Evening.
10:00 morning.
10:00 a.m.Before noon.
6:00 evening dinner.
6:00 p.m.After noon.
1:00 after midnight.
1:00 a.m.Early morning.
11:30 before noon.
11:30 a.m.Morning.
11:30 night.
11:30 p.m.Before midnight.
12:00 noon.
12:00 p.m.Noon boundary.
12:00 midnight.
12:00 a.m.Midnight boundary.
Why two7:00s?
Clock repeats every12 hoursa.m./p.m. distinguishes.
School starts8:00 likely?
a.m.Morning start.
Bedtime9:00 likely?
p.m.Night.
Lunch12:30 likely?
p.m.After noon.
Breakfast6:30 likely?
a.m.Morning.
Sunset7:45 likely?
p.m.Evening.
Doctor10:15 morning.
a.m.Specified morning.
Movie7:30 evening.
p.m.Specified evening.
Which comes first in day:9a.m. or9p.m.?
9a.m.Morning precedes evening.
Explain12-hour labels.
a.m. and p.m. distinguish repeated clock readingsSame face time can refer to two daily moments.
Practice
Guided practice with hints
018:00 before school.
Hint: Morning label.
Answer: a.m.
024:00 after school.
Hint: Afternoon label.
Answer: p.m.
0311:00 night.
Hint: Night.
Answer: p.m.
046:30 morning.
Hint: Morning.
Answer: a.m.
0512 noon label.
Hint: Boundary after morning.
Answer: p.m.
06Why need label?
Hint: Clock repeats.
Answer: To distinguish two daily occurrences.
Practice
Independent practice
017:15 morning
Answer: a.m.
023:45 afternoon
Answer: p.m.
039:00 evening
Answer: p.m.
0410:30 morning
Answer: a.m.
0512 noon
Answer: p.m.
0612 midnight
Answer: a.m.
07Which earlier:8a.m or8p.m
Answer: 8a.m.
08Why same time number twice?
Answer: 12-hour cycle repeats.
Common mistakes
Learn to catch the error, not just the answer.
12 noon begins p.m.;12 midnight begins a.m.
Use activity and day period to choose label.
P.M. includes afternoon and evening after noon.
Applications & challenge
Use the idea beyond a single exercise.
Applications
- Read school, transit, and appointment schedules.
- Label daily routines with morning/afternoon/evening times.
Challenge problems
Why is12:01 p.m. after noon?
P.M. begins at noon.
Why is12:01 a.m. after midnight?
A.M. begins at midnight.
Could7:00 be both breakfast and dinner time?
Yes,7a.m. and7p.m.
How could you avoid12a.m./p.m. confusion?
Say midnight or noon explicitly.
Flashcards
Retrieve it from memory.
Flashcards
Card 1 of 6
Game mode
Day Planner
Place activities at plausible a.m./p.m. times on a daily timeline.
Practice
Mastery check
018 morning
Answer: a.m.
025 afternoon
Answer: p.m.
0310 night
Answer: p.m.
0412 noon
Answer: p.m.
0512 midnight
Answer: a.m.
06Why labels needed?
Answer: Clock readings repeat every12 hours.
07P.M. begins when?
Answer: Noon
08A.M. begins when?
Answer: Midnight
Terminology
Words to know
- a.m.
- The12-hour period from midnight to before noon.
- p.m.
- The12-hour period from noon to before midnight.
- noon
- 12:00 in the middle of the day.
- midnight
- 12:00 at the start/end boundary of a calendar day.
Continue learning
Connected concepts
Curriculum references
Standards and instructional references
California Common Core State Standards for Mathematics — 2.MD.C.7 and time context
Time reading and daily time interpretation.