PERCENTAGE
1. Mistakes made when converting fractions to percentages.
Example : 3/5 = ______ %
3/5 = _____ % 3/5 = ____ %
3/5 = ( 3/5 ) % 3/5 = (3 x 20) / (5 x 20) = 60 / 100
= 0.6 % (wrong) = 60 % (correct)
2. Mistakes made when converting percentages to decimals
Example : Convert 275 % to a decimals.
275 % = 275/100 x 100 275 % = 275/100
= 275 (wrong) = 2.75 (correct)
3. Mistakes in counting percentages
Example : 5 % of 200
5 % of 200 = 5 x 200 5 % of 200 = 5/100 x 200
= 1 000 (wrong) = 10 (correct)
MONEY
1. Mistakes made when adding and subtracting money, decimal point must be arranged in a straight line.
Example : RM 567.20 + RM 12 + RM 4 208 =
2. Mistakes made when performing operations involving brackets. Calculation must be done in brackets first.
Example : RM 7 325.55 x ( 5 + 4 ) =
TIME
1. Mistakes in the units of measurements of time.
Example : 5 hr 42 min + 3 hr 50 min =
5 hr 42 min + 3 hr 50 min = 8 hr 92 min ( wrong ) because 92 min is more than 1 hour
5 hr 42 min + 3 hr 50 min = 9 hr 32 min (correct )
2. Mistakes in calculating the numbers of days between two given dates.
Example : Calculate the number of days between 19 Sept 2008 and 28 Sept 2008
Number of days from 19-28 Sept. 2008
= ( 28 - 19 ) days
= 9 days (wrong)
Number of days from 19-28 Sept. 2008
= ( 28 - 19 + 1 ) days
= 10 days (correct)
( 19 Sept. 2008 is count as 1 day )
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