Grade 3 · Cross an hour boundary with minutes · 562 of 750
Cross an hour boundary with minutes: starting whole hour: 12; duration: 175 minutes
An activity at a classroom activity starts at 12:00 and runs for 175 minutes. Find the clock reading at the planned end, explain the calculation, and check a related question.
Try the question, use a hint when you need one, and compare your reasoning with the worked solution. The animation starts with this chapter’s values; changing its controls explores a new case.
01 · Make a prediction
Your practice question
An activity at a classroom activity starts at 12:00 and runs for 175 minutes. First find the clock reading at the planned end. Then answer: What would the clock read five minutes after the planned end?
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A starting point
The minute hand completes one revolution in sixty minutes while the hour hand moves continuously. Crossing the twelve mark on the minute hand can change the hour without resetting elapsed time.
Work through the reasoning
Step 1
Identify the quantities and the task
An activity at a classroom activity starts at 12:00 and runs for 175 minutes. The first task is to find the clock reading at the planned end. The minute hand completes one revolution in sixty minutes while the hour hand moves continuously. Crossing the twelve mark on the minute hand can change the hour without resetting elapsed time.
Step 2
Calculate the original result
12:00 + 175 minutes = 2:55. After 175 minutes the clock reads 2:55. A clock reading is a position in a twelve-hour cycle; the duration records how much time passed.
Step 3
Complete the follow-up calculation
What would the clock read five minutes after the planned end? 3:00. Add five to the elapsed duration, carrying sixty minutes into the next hour when necessary.
The answer
12:00 + 175 minutes = 2:55. After 175 minutes the clock reads 2:55. A clock reading is a position in a twelve-hour cycle; the duration records how much time passed. Follow-up: 3:00. Add five to the elapsed duration, carrying sixty minutes into the next hour when necessary.
Compare the method as well as the result. A different valid method may reach the same answer. Keep exact values until the last step when the question asks for rounding.
02 · Explore the model
See the mathematical relationship move.
Use Play, Pause, and the timeline to inspect the construction. Reset restores the question’s original settings. The displayed assumptions describe where this model applies.
Watch the relationship
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The mathematical idea
An activity at a classroom activity starts at 12:00 and runs for 175 minutes. The minute hand completes one revolution in sixty minutes while the hour hand moves continuously. Crossing the twelve mark on the minute hand can change the hour without resetting elapsed time. After 175 minutes the clock reads 2:55. A clock reading is a position in a twelve-hour cycle; the duration records how much time passed.
12:00 + 175 minutes = 2:55
03 · Reflect and transfer
Explain what changes and why.
Move the timeline to advance elapsed minutes. Read the minute hand first and notice the hour hand's movement between numbered hours. Explain which quantity changes and which relationship stays valid. Use the starting values again before checking your written answer.
This is a distinct guided scenario using a reusable mathematical model. Similar-looking diagrams can represent different given values and conclusions; they are not different mathematical theories.