Let's solve each subtraction problem step by step. We are subtracting time values in hours, minutes, and seconds. When the lower number is greater than the upper number in a unit (e.g., minutes or seconds), we need to
borrow from the next higher unit.
---
1. 89 hr 23 min - 81 hr 08 min
- Hours: 89 - 81 = 8
- Minutes: 23 - 8 = 15
✔ Answer: 8 hr 15 min
---
2. 35 hr 32 min - 22 hr 16 min
- Hours: 35 - 22 = 13
- Minutes: 32 - 16 = 16
✔ Answer: 13 hr 16 min
---
3. 40 min 25 sec - 35 min 43 sec
- Seconds: 25 < 43 → borrow 1 minute (60 sec)
- 25 + 60 = 85 sec
- 85 - 43 = 42 sec
- Minutes: 40 - 1 (borrowed) = 39; 39 - 35 = 4
✔ Answer: 4 min 42 sec
---
4. 69 hr 54 min - 45 hr 50 min
- Hours: 69 - 45 = 24
- Minutes: 54 - 50 = 4
✔ Answer: 24 hr 4 min
---
5. 57 min 43 sec - 23 min 41 sec
- Seconds: 43 - 41 = 2
- Minutes: 57 - 23 = 34
✔ Answer: 34 min 2 sec
---
6. 27 min 19 sec - 26 min 45 sec
- Seconds: 19 < 45 → borrow 1 minute
- 19 + 60 = 79
- 79 - 45 = 34 sec
- Minutes: 27 - 1 = 26; 26 - 26 = 0
✔ Answer: 0 hr 0 min 34 sec →
34 sec
---
7. 49 min 50 sec - 33 min 47 sec
- Seconds: 50 - 47 = 3
- Minutes: 49 - 33 = 16
✔ Answer: 16 min 3 sec
---
8. 83 hr 56 min - 26 hr 05 min
- Hours: 83 - 26 = 57
- Minutes: 56 - 5 = 51
✔ Answer: 57 hr 51 min
---
9. 55 min 14 sec - 44 min 12 sec
- Seconds: 14 - 12 = 2
- Minutes: 55 - 44 = 11
✔ Answer: 11 min 2 sec
---
10. 52 hr 48 min - 50 hr 57 min
- Minutes: 48 < 57 → borrow 1 hour
- 48 + 60 = 108 min
- 108 - 57 = 51 min
- Hours: 52 - 1 = 51; 51 - 50 = 1
✔ Answer: 1 hr 51 min
---
11. 43 hr 08 min - 42 hr 46 min
- Minutes: 8 < 46 → borrow 1 hour
- 8 + 60 = 68
- 68 - 46 = 22 min
- Hours: 43 - 1 = 42; 42 - 42 = 0
✔ Answer: 0 hr 22 min →
22 min
---
12. 81 hr 53 min - 77 hr 09 min
- Hours: 81 - 77 = 4
- Minutes: 53 - 9 = 44
✔ Answer: 4 hr 44 min
---
13. 45 min 50 sec - 27 min 05 sec
- Seconds: 50 - 5 = 45
- Minutes: 45 - 27 = 18
✔ Answer: 18 min 45 sec
---
14. 31 min 20 sec - 27 min 11 sec
- Seconds: 20 - 11 = 9
- Minutes: 31 - 27 = 4
✔ Answer: 4 min 9 sec
---
15. 55 min 52 sec - 37 min 29 sec
- Seconds: 52 - 29 = 23
- Minutes: 55 - 37 = 18
✔ Answer: 18 min 23 sec
---
##
✔ Final Answers:
1.
8 hr 15 min
2.
13 hr 16 min
3.
4 min 42 sec
4.
24 hr 4 min
5.
34 min 2 sec
6.
34 sec
7.
16 min 3 sec
8.
57 hr 51 min
9.
11 min 2 sec
10.
1 hr 51 min
11.
22 min
12.
4 hr 44 min
13.
18 min 45 sec
14.
4 min 9 sec
15.
18 min 23 sec
Let me know if you'd like this formatted for printing or as a worksheet!
Parent Tip: Review the logic above to help your child master the concept of adding and subtracting irregular units worksheet.
