Time worksheet

1. Resulting duration: 10 h 19 min 28 s

1. Turn the starting duration into seconds, so everything uses one unit (3,600 per hour, 60 per minute)

   $3\times \mathrm{3,600}+50\times 60+26$$=\mathrm{13,826}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds the same way

   $6\times \mathrm{3,600}+29\times 60+2$$=\mathrm{23,342}\text{\hspace{0.17em}s}$

3. Add the amount

   $\mathrm{13,826}+\mathrm{23,342}$$=\mathrm{37,168}\text{\hspace{0.17em}s}$

4. Turn the seconds back into hours, minutes and seconds

   $\mathrm{37,168}\text{\hspace{0.17em}s}$$=10\times \mathrm{3,600}+19\times 60+28$$=\text{10 h 19 min 28 s}$

5. For decimal hours (handy for timesheets), divide the seconds by 3,600

   $\frac{\mathrm{37,168}}{\mathrm{3,600}}$$=10.3244\text{\hspace{0.17em}h}$

2. Resulting duration: −3 h 39 min 24 s

1. Turn the starting duration into seconds, so everything uses one unit (3,600 per hour, 60 per minute)

   $2\times \mathrm{3,600}+50\times 60+36$$=\mathrm{10,236}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds the same way

   $6\times \mathrm{3,600}+30\times 60+0$$=\mathrm{23,400}\text{\hspace{0.17em}s}$

3. Subtract the amount

   $\mathrm{10,236}-\mathrm{23,400}$$=\mathrm{-13,164}\text{\hspace{0.17em}s}$

4. The result is negative, so split its size into hours, minutes and seconds and keep the minus sign

   $\mathrm{13,164}\text{\hspace{0.17em}s}$$=3\times \mathrm{3,600}+39\times 60+24$$=\text{−3 h 39 min 24 s}$

5. For decimal hours (handy for timesheets), divide the seconds by 3,600

   $\frac{\mathrm{-13,164}}{\mathrm{3,600}}$$=\mathrm{-3.6567}\text{\hspace{0.17em}h}$

3. Resulting time: 3:18 AM

1. Turn the start time into seconds after midnight, so everything uses one unit

   $12\times \mathrm{3,600}+54\times 60+0$$=\mathrm{46,440}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds too (3,600 per hour, 60 per minute)

   $9\times \mathrm{3,600}+36\times 60+0$$=\mathrm{34,560}\text{\hspace{0.17em}s}$

3. Subtract the amount

   $\mathrm{46,440}-\mathrm{34,560}$$=\mathrm{11,880}\text{\hspace{0.17em}s}$

4. Turn the seconds back into hours, minutes and seconds on a 24-hour clock

   $\mathrm{11,880}\text{\hspace{0.17em}s}$$=3\times \mathrm{3,600}+18\times 60+0$$=\text{03:18}$

5. Write it the everyday way, on a 12-hour clock with AM or PM

   $\text{03:18}$$=\text{3:18 AM}$

4. Resulting duration: −4 h 33 min 30 s

1. Turn the starting duration into seconds, so everything uses one unit (3,600 per hour, 60 per minute)

   $2\times \mathrm{3,600}+50\times 60+30$$=\mathrm{10,230}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds the same way

   $7\times \mathrm{3,600}+24\times 60+0$$=\mathrm{26,640}\text{\hspace{0.17em}s}$

3. Subtract the amount

   $\mathrm{10,230}-\mathrm{26,640}$$=\mathrm{-16,410}\text{\hspace{0.17em}s}$

4. The result is negative, so split its size into hours, minutes and seconds and keep the minus sign

   $\mathrm{16,410}\text{\hspace{0.17em}s}$$=4\times \mathrm{3,600}+33\times 60+30$$=\text{−4 h 33 min 30 s}$

5. For decimal hours (handy for timesheets), divide the seconds by 3,600

   $\frac{\mathrm{-16,410}}{\mathrm{3,600}}$$=\mathrm{-4.5583}\text{\hspace{0.17em}h}$

5. Resulting duration: 9 h 12 min 33 s

1. Turn the starting duration into seconds, so everything uses one unit (3,600 per hour, 60 per minute)

   $3\times \mathrm{3,600}+44\times 60+30$$=\mathrm{13,470}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds the same way

   $5\times \mathrm{3,600}+28\times 60+3$$=\mathrm{19,683}\text{\hspace{0.17em}s}$

3. Add the amount

   $\mathrm{13,470}+\mathrm{19,683}$$=\mathrm{33,153}\text{\hspace{0.17em}s}$

4. Turn the seconds back into hours, minutes and seconds

   $\mathrm{33,153}\text{\hspace{0.17em}s}$$=9\times \mathrm{3,600}+12\times 60+33$$=\text{9 h 12 min 33 s}$

5. For decimal hours (handy for timesheets), divide the seconds by 3,600

   $\frac{\mathrm{33,153}}{\mathrm{3,600}}$$=9.2092\text{\hspace{0.17em}h}$

6. Resulting time: 6:10:59 AM

1. Turn the start time into seconds after midnight, so everything uses one unit

   $13\times \mathrm{3,600}+47\times 60+0$$=\mathrm{49,620}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds too (3,600 per hour, 60 per minute)

   $7\times \mathrm{3,600}+36\times 60+1$$=\mathrm{27,361}\text{\hspace{0.17em}s}$

3. Subtract the amount

   $\mathrm{49,620}-\mathrm{27,361}$$=\mathrm{22,259}\text{\hspace{0.17em}s}$

4. Turn the seconds back into hours, minutes and seconds on a 24-hour clock

   $\mathrm{22,259}\text{\hspace{0.17em}s}$$=6\times \mathrm{3,600}+10\times 60+59$$=\text{06:10:59}$

5. Write it the everyday way, on a 12-hour clock with AM or PM

   $\text{06:10:59}$$=\text{6:10:59 AM}$

7. Resulting duration: −4 h 49 min 25 s

1. Turn the starting duration into seconds, so everything uses one unit (3,600 per hour, 60 per minute)

   $2\times \mathrm{3,600}+40\times 60+36$$=\mathrm{9,636}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds the same way

   $7\times \mathrm{3,600}+30\times 60+1$$=\mathrm{27,001}\text{\hspace{0.17em}s}$

3. Subtract the amount

   $\mathrm{9,636}-\mathrm{27,001}$$=\mathrm{-17,365}\text{\hspace{0.17em}s}$

4. The result is negative, so split its size into hours, minutes and seconds and keep the minus sign

   $\mathrm{17,365}\text{\hspace{0.17em}s}$$=4\times \mathrm{3,600}+49\times 60+25$$=\text{−4 h 49 min 25 s}$

5. For decimal hours (handy for timesheets), divide the seconds by 3,600

   $\frac{\mathrm{-17,365}}{\mathrm{3,600}}$$=\mathrm{-4.8236}\text{\hspace{0.17em}h}$

8. Resulting time: 6:37 PM

1. Turn the start time into seconds after midnight, so everything uses one unit

   $12\times \mathrm{3,600}+5\times 60+0$$=\mathrm{43,500}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds too (3,600 per hour, 60 per minute)

   $6\times \mathrm{3,600}+32\times 60+0$$=\mathrm{23,520}\text{\hspace{0.17em}s}$

3. Add the amount

   $\mathrm{43,500}+\mathrm{23,520}$$=\mathrm{67,020}\text{\hspace{0.17em}s}$

4. Turn the seconds back into hours, minutes and seconds on a 24-hour clock

   $\mathrm{67,020}\text{\hspace{0.17em}s}$$=18\times \mathrm{3,600}+37\times 60+0$$=\text{18:37}$

5. Write it the everyday way, on a 12-hour clock with AM or PM

   $\text{18:37}$$=\text{6:37 PM}$

9. Resulting time: 6:05 PM

1. Turn the start time into seconds after midnight, so everything uses one unit

   $9\times \mathrm{3,600}+37\times 60+0$$=\mathrm{34,620}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds too (3,600 per hour, 60 per minute)

   $8\times \mathrm{3,600}+28\times 60+0$$=\mathrm{30,480}\text{\hspace{0.17em}s}$

3. Add the amount

   $\mathrm{34,620}+\mathrm{30,480}$$=\mathrm{65,100}\text{\hspace{0.17em}s}$

4. Turn the seconds back into hours, minutes and seconds on a 24-hour clock

   $\mathrm{65,100}\text{\hspace{0.17em}s}$$=18\times \mathrm{3,600}+5\times 60+0$$=\text{18:05}$

5. Write it the everyday way, on a 12-hour clock with AM or PM

   $\text{18:05}$$=\text{6:05 PM}$

10. Resulting duration: −5 h 35 min 38 s

1. Turn the starting duration into seconds, so everything uses one unit (3,600 per hour, 60 per minute)

   $2\times \mathrm{3,600}+55\times 60+25$$=\mathrm{10,525}\text{\hspace{0.17em}s}$

2. Turn the amount into seconds the same way

   $8\times \mathrm{3,600}+31\times 60+3$$=\mathrm{30,663}\text{\hspace{0.17em}s}$

3. Subtract the amount

   $\mathrm{10,525}-\mathrm{30,663}$$=\mathrm{-20,138}\text{\hspace{0.17em}s}$

4. The result is negative, so split its size into hours, minutes and seconds and keep the minus sign

   $\mathrm{20,138}\text{\hspace{0.17em}s}$$=5\times \mathrm{3,600}+35\times 60+38$$=\text{−5 h 35 min 38 s}$

5. For decimal hours (handy for timesheets), divide the seconds by 3,600

   $\frac{\mathrm{-20,138}}{\mathrm{3,600}}$$=\mathrm{-5.5939}\text{\hspace{0.17em}h}$