When it comes to the mathematics topic, Time, Hour and Minute. Many students tend to have some misconceptions and bound to make the following mistakes. Students should avoid making such blunders, in a bid to secure the marks in their test.
Mistake 1:
Convert 0.30hr to mins.
0.30hr is NOT equal to 30min but Equal to 18min
Working:
0.30hr = 0hr and 0.30hr
30/100 x 60min = 18min
Convert 5.50hr to Hrs and Mins.
5.50hr is NOT equal to 5hr 50min but Equal to 5hr 30min
Correct Working:
5.50hr = 5hr and 0.50hr
5hr + 50/100 x 60min = 5hr 30min
Mistake 2:
Convert 0.40min to secs.
0.40min is NOT equal to 40sec but Equal to 24sec
Correct Working:
0.40min = 0min and 0.40min
40/100 x 60sec = 24sec
Mistake 3:
Convert 45min to hour.
Common Mistake:
Students will derive the answer as 0.45hour.
Correct Working:
45/60 = 0.75hour
Mistake 4:
Convert 12sec to min.
Common Mistake:
Students will derive the answer as 0.12min.
Correct Working:
12/60 = 0.2min
Mistake 5:
Adam left house at 11.45am and reached school at 1.15pm. How long did he take to reach school?
Students forget to convert time in pm to 24hr format, that is 115pm to 1315hr.
Mistake 6:
When the number at Min column is too small to deduct a bigger number, after borrowing from the Hr column, students add 1 to the Min column
Correct Working:
Student should first change 115pm to 1315hr.
After borrowing 1 hr from the Hr column, add 60min to 15min to become 75min.
Take 75min – 45min = 30min
Thus Adam took 1hr 30min to reach school.
Above are some common mistakes made by students while doing practices or during exam. Hope students can take note to avoid marks lost due to these mistakes. I welcome comments or suggestions. 🙂
krizteotuition.wordpress.com 