Telling and Writing Time to the Half-Hour (:30) - First Grade Mathematics

As time moves forward, the hands on a clock do not stay frozen! After thirty minutes pass, the long minute hand has traveled halfway around the clock circle, landing straight down on the number 6. At the exact same time, something subtle happens to the short hour hand: it glides halfway between two numbers! Telling time to the half-hour requires a keen eye to notice this hour-hand movement. In this chapter, you will master reading and writing time to the half-hour, learn why the minute hand points to 6, and understand where the hour hand rests.

The Half-Hour Journey of the Minute Hand

A full hour has 60 minutes. Half of 60 is 30!

The Minute Hand's Half Lap:
Top of the clock:   12 (0 minutes)
                    |  (Travels clockwise down the right side...)
                    v
Bottom of clock:     6 (30 MINUTES!)

Why 6 Means 30 Minutes

When counting minutes, each of the twelve numbers represents 5 minutes: 1 is 5 min, 2 is 10 min, 3 is 15 min, 4 is 20 min, 5 is 25 min, and 6 is 30 MINUTES! Whenever the long minute hand points straight down to 6, exactly 30 minutes have passed in the hour.

The Sneaky Hour Hand: Halfway Between Two Numbers!

Here is the trickiest trap in reading an analog clock: when the time is half-past, the hour hand does NOT point directly at a number!

Clock Showing 4:30:
                 12
            11        1
        10                2
       9          +         3
        8          \      4   <- Hour hand is HALFWAY between 4 and 5!
             7   \    5
                 (6)  <--- Minute Hand points straight down to 6!

The Rule of the Hour Hand at :30

Because half the hour has already gone by, the hour hand has traveled halfway on its journey toward the next number! At 4:30, the hour hand sits halfway between 4 and 5. At 7:30, the hour hand sits halfway between 7 and 8. At 1:30, the hour hand sits halfway between 1 and 2.

Which Hour Is It? Look at Who Came First!

If the hour hand is resting between 4 and 5, which hour is it? It is still the 4 o'clock hour because the hand has passed 4, but has not yet reached 5! Always name the number that the hour hand has just passed.

Writing Half-Hour Times

Digital clocks display half-hours with a :30 after the colon.

Half-Hour Time Formats:
Digital:       Word Phrase:
 1:30          One-thirty (or Half-past one)
 4:30          Four-thirty (or Half-past four)
 8:30          Eight-thirty (or Half-past eight)
11:30          Eleven-thirty (or Half-past eleven)

Practice Exercises

Exercise 1: When the minute hand points straight down to the 6, how many minutes have passed in the hour?

Exercise 2: Look at an analog clock. The long minute hand points to 6. The short hour hand is halfway between 8 and 9. What time is it? Write the time in digital format.

Exercise 3: A student looks at an analog clock showing 2:30. The student thinks the time is 3:30 because the hour hand is close to the 3. Explain how to determine the correct hour.

Exercise 4: Write the digital time for each phrase: Six-thirty = : Half-past nine = : Twelve-thirty = :

Solutions and Explanations

Solution to Exercise 1: Exactly 30 minutes have passed in the hour.

Solution to Exercise 2: The time is 8:30 (eight-thirty). The hour hand has passed 8 but has not reached 9, so the hour is 8, and the minute hand on 6 indicates 30 minutes.

Solution to Exercise 3: Look at the clockwise direction of the hour hand. The hand starts at 2 and travels toward 3. When it is halfway between 2 and 3, it has passed 2, but has not arrived at 3 yet. Therefore, it is still the 2 o'clock hour (2:30), not 3:30.

Solution to Exercise 4: Six-thirty = 6:30 Half-past nine = 9:30 Twelve-thirty = 12:30