Here are the step-by-step solutions for adding and subtracting the times.
1. Add the following times:
a) 4hr 15min + 3hr 20min
*
Add minutes: $15 + 20 = 35$ minutes.
*
Add hours: $4 + 3 = 7$ hours.
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Result: 7hr 35min
b) 6hr 25min + 3hr 30min
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Add minutes: $25 + 30 = 55$ minutes.
*
Add hours: $6 + 3 = 9$ hours.
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Result: 9hr 55min
c) 3hr 35min + 2hr 35min
*
Add minutes: $35 + 35 = 70$ minutes.
* Since 70 minutes is more than 60, we convert it: $70 - 60 = 10$ minutes, and carry over 1 hour.
*
Add hours: $3 + 2 = 5$ hours. Add the carried over hour: $5 + 1 = 6$ hours.
*
Result: 6hr 10min
d) 8hr 45min + 5hr 55min
*
Add minutes: $45 + 55 = 100$ minutes.
* Convert minutes: $100 - 60 = 40$ minutes, and carry over 1 hour.
*
Add hours: $8 + 5 = 13$ hours. Add the carried over hour: $13 + 1 = 14$ hours.
*
Result: 14hr 40min
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2. Subtract the following:
a) 6hr 57min - 2hr 35min
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Subtract minutes: $57 - 35 = 22$ minutes.
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Subtract hours: $6 - 2 = 4$ hours.
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Result: 4hr 22min
b) 7hr 48min - 4hr 37min
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Subtract minutes: $48 - 37 = 11$ minutes.
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Subtract hours: $7 - 4 = 3$ hours.
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Result: 3hr 11min
c) 9hr 25min - 5hr 45min
*
Subtract minutes: You cannot subtract 45 from 25.
* Borrow 1 hour from the 9 hours (leaving 8 hours).
* Add 60 minutes to the 25 minutes: $25 + 60 = 85$ minutes.
* Now subtract: $85 - 45 = 40$ minutes.
*
Subtract hours: $8 - 5 = 3$ hours.
*
Result: 3hr 40min
d) 11hr 12min - 1hr 54min
*
Subtract minutes: You cannot subtract 54 from 12.
* Borrow 1 hour from the 11 hours (leaving 10 hours).
* Add 60 minutes to the 12 minutes: $12 + 60 = 72$ minutes.
* Now subtract: $72 - 54 = 18$ minutes.
*
Subtract hours: $10 - 1 = 9$ hours.
*
Result: 9hr 18min
Final Answer:
1. Add the following times:
a) 7hr 35min
b) 9hr 55min
c) 6hr 10min
d) 14hr 40min
2. Subtract the following:
a) 4hr 22min
b) 3hr 11min
c) 3hr 40min
d) 9hr 18min
Parent Tip: Review the logic above to help your child master the concept of adding time worksheet.
