Add hours and quarter hours
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Add hours and quarter hours: skill guide
| Objective | Learners find the ending time after adding 15, 30, or 45 minutes or 1, 2, or 3 hours to a digital time. |
|---|---|
| Grade | Grade 1 |
| Standard | CCSS.MATH.CONTENT.3.MD.A.1 |
| Difficulty | Developing · Mixed |
| Representation | Numerical equation, Digital clock |
| Practice format | Interactive, account-free practice with immediate feedback |
Objective
Learners find the ending time after adding 15, 30, or 45 minutes or 1, 2, or 3 hours to a digital time.
What this practice covers
Learners see a starting time on a digital clock and an amount to add, then choose the ending time from five choices. Every starting time is on the hour or at :15, :30, or :45. Early problems that add minutes stay within the hour. The last problems cross into the next hour and can go from 11 to 12, as in 11:45 plus 45 minutes is 12:30. Choose a 5-question Quick check or a 15-question Practice session; the difficulty progression adjusts to the selected length.
Standards alignment
Prepares for Common Core: CCSS.MATH.CONTENT.3.MD.A.1 — Tell and write time to the nearest minute and measure time intervals in minutes.
Who it’s for
This practice is designed for Grade 1 learners building an early understanding of clocks and time. It is also useful for older learners who want a calm visual review of how hours and minutes are represented.
What to know first
- Learners should read digital times and know that 60 minutes make one hour.
Difficulty and scaffolding
Developing · Mixed stage
Problem representations
- Numerical equation
- Digital clock
Three worked examples
- Start at 2:00 and add 1 hour. The hour goes up by one, so the ending time is 3:00.
- Start at 4:15 and add 30 minutes. 15 + 30 = 45, so the ending time is 4:45.
- Start at 11:45 and add 45 minutes. 15 minutes reaches 12:00, and 30 more makes 12:30.
Likely misconceptions
- Learners may add the minutes to the hour, or keep the same hour after the minutes pass 60. For example, 10:45 plus 30 minutes is 11:15. Count 15 minutes to reach 11:00, then add the 15 minutes that are left.
Hints and explanations
- Start at 2:00 and add 1 hour. The hour goes up by one, so the ending time is 3:00.
- Start at 4:15 and add 30 minutes. 15 + 30 = 45, so the ending time is 4:45.
- Start at 11:45 and add 45 minutes. 15 minutes reaches 12:00, and 30 more makes 12:30.
What to practice next
Next, practice analog time to 5 minutes, which returns to the clock face and uses any multiple of 5 minutes.
Editorial review
Reviewed by Brilliant’s curriculum team. Exercises are generated within defined difficulty ranges and checked against verified answer rules.
Add hours and quarter hours FAQs
What does add hours and quarter hours teach?
It teaches learners to find a later time by counting on from a starting time. They add whole hours by changing the hour and add 15, 30, or 45 minutes by counting on in quarter hours.
What happens when the minutes pass the hour?
An hour has 60 minutes, so the minutes start over at 00 and the hour goes up by one. To add 30 minutes to 3:45, count 15 minutes to 4:00, then 15 more to 4:15.
Should telling-time practice be timed?
No timer is necessary. Accuracy and explanation should come first. Ask the learner to say the starting time, count on by the amount added, and then check whether the hour should change.
How can an adult help after a mistake?
Have the learner read the starting time aloud, then count on in steps of 15 minutes or 1 hour until the full amount is added. Keep the correction brief and let the learner retry the same problem before showing the answer.