Add and subtract mixed time units

key notes :

1. Understanding Time Units

  • Seconds (s), Minutes (min), Hours (h), Days (d)
  • Conversions:
    • 1 minute = 60 seconds
    • 1 hour = 60 minutes
    • 1 day = 24 hours

2. Adding Mixed Time Units

  • Step 1: Add seconds first. If the sum is 60 or more, convert to minutes.
  • Step 2: Add minutes. If the sum is 60 or more, convert to hours.
  • Step 3: Add hours and adjust if necessary.

Example:
3 hours 45 minutes + 2 hours 50 minutes

  1. Add minutes: 45 + 50 = 95 minutes (Convert 60 minutes → 1 hour, remaining 35 minutes)
  2. Add hours: 3 + 2 + 1 (carried) = 6 hours
    Final Answer: 6 hours 35 minutes

3. Subtracting Mixed Time Units

  • Step 1: If needed, borrow from the larger unit (1 hour = 60 minutes, 1 minute = 60 seconds).
  • Step 2: Subtract minutes and seconds separately.

Example:
5 hours 20 minutes – 2 hours 45 minutes

  1. Not enough minutes (20 < 45), so borrow 1 hour = 60 minutes
    • Now, 4 hours 80 minutes
  2. Subtract minutes: 80 – 45 = 35 minutes
  3. Subtract hours: 4 – 2 = 2 hours
    Final Answer: 2 hours 35 minutes

Learn with an example

📢 1 hour 53 minutes − 1 hour 2 minutes

= _____ hours ______ minutes

Subtract hours from hours and minutes from minutes.

1 hour 53 minutes − 1 hour 2 minutes = 0 hours 51 minutes

📢 Add: 3 weeks 2 days + 2 weeks 2 days = _____ weeks _______ days

Add the times. Add weeks to weeks and days to days.

3 weeks 2 days + 2 weeks 2 days = 5 weeks 4 days

📢 Add: 4 weeks 1 day + 4 weeks 1 day = ____ weeks _______ days

Add the times. Add weeks to weeks and days to days.

4 weeks 1 day + 4 weeks 1 day = 8 weeks 2 days

Let’s practice!🖊️