What is Adding and Subtracting Time in Minutes?

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Grade Level:

Class 2

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Definition

What is it?

Adding and subtracting time in minutes means combining or taking away durations of time, specifically when those durations are measured in minutes. It helps us figure out how long an activity lasts or when something will start/end.

Simple Example

Quick Example

Imagine your favourite TV show starts at 7:00 PM and runs for 30 minutes. To find out when it ends, you would add 30 minutes to 7:00 PM. So, it ends at 7:30 PM.

Worked Example

Step-by-Step

Let's say a train journey takes 45 minutes to reach Station A and then another 20 minutes to reach Station B. What is the total journey time from the start to Station B?

Step 1: Identify the times to be added. Journey 1 = 45 minutes, Journey 2 = 20 minutes.
---Step 2: Add the minutes together: 45 + 20.
---Step 3: Perform the addition: 45 + 20 = 65 minutes.
---Step 4: Convert minutes if they are 60 or more. Since 65 minutes is more than 60 minutes, we know 60 minutes = 1 hour.
---Step 5: Subtract 60 minutes from 65 minutes to find the remaining minutes: 65 - 60 = 5 minutes.
---Step 6: So, 65 minutes is 1 hour and 5 minutes.

Answer: The total journey time is 1 hour and 5 minutes.

Why It Matters

Understanding how to add and subtract time is crucial for managing schedules in daily life and in many exciting careers. From planning flight schedules as an airline pilot to scheduling project deadlines as a software engineer, or even calculating the exact launch window for a satellite at ISRO, time management is key.

Common Mistakes

MISTAKE: Treating minutes like regular base-10 numbers when they go over 60 (e.g., 40 minutes + 30 minutes = 70 minutes, and thinking 70 minutes is 1 hour and 10 minutes, but not realizing it's 1 hour and 10 minutes). | CORRECTION: Remember that there are 60 minutes in 1 hour. When your minutes sum up to 60 or more, convert groups of 60 minutes into hours.

MISTAKE: Not carrying over or borrowing correctly when adding/subtracting across hours (e.g., subtracting 30 minutes from 1 hour results in -30 minutes). | CORRECTION: When you need to subtract more minutes than you have, borrow 1 hour from the hour column and convert it to 60 minutes. Then subtract from the total minutes.

MISTAKE: Forgetting to adjust the hour part after converting minutes to hours (e.g., 80 minutes becomes 1 hour 20 minutes, but forgetting to add that '1 hour' to the existing hours). | CORRECTION: Always add the 'carried over' hours to the existing hours, or subtract 'borrowed' hours from the existing hours.

Practice Questions

Try It Yourself

QUESTION: Your tuition class starts at 5:00 PM and lasts for 45 minutes. When does it end? | ANSWER: 5:45 PM

QUESTION: A chef needs to bake a cake for 35 minutes and then let it cool for 15 minutes. How much total time is needed for baking and cooling? | ANSWER: 50 minutes

QUESTION: A bus left the stand at 9:10 AM. It took 50 minutes to reach its first stop. What time did it reach the first stop? | ANSWER: 10:00 AM

MCQ

Quick Quiz

Your favourite cricket match highlights run for 25 minutes. If you start watching at 8:30 PM, when will the highlights finish?

1899-12-30T20:50:00.000Z

1899-12-30T20:55:00.000Z

1899-12-30T21:00:00.000Z

1899-12-30T21:05:00.000Z

The Correct Answer Is:

Starting at 8:30 PM and adding 25 minutes means 30 + 25 = 55 minutes. So, the time will be 8:55 PM. No hour conversion is needed as 55 minutes is less than 60.

Real World Connection

In the Real World

From planning your daily schedule with a timetable to understanding how long it will take for your Swiggy or Zomato order to arrive, adding and subtracting minutes is used everywhere. Even traffic apps like Google Maps calculate your estimated arrival time by adding journey durations.

Key Vocabulary

Key Terms

DURATION: The length of time that something continues or lasts | CONVERT: To change the form, character, or function of something | HOUR: A unit of time equal to 60 minutes | MINUTE: A unit of time equal to 60 seconds

What's Next

What to Learn Next

Great job learning about adding and subtracting time in minutes! Next, you should explore 'Adding and Subtracting Time in Hours and Minutes'. This will build on what you've learned and help you handle even longer durations more easily.