LENGTH
1. Mistakes when subtracting , adding, multilying or dividing involving conversion of units.
Example :
a) 76.8 m - 51 cm = 25.8 m (wrong because cm was not converted to m )
76.8 m - 51 cm = 76.29 m (correct )
b) 432 m x 16 = 6 912 km ( wrong to change the unit without converting the value )
432 m x 16 = 6.912 km (correct)
MASS
1. Mistakes in calculation involving different units.
Example :
a) 6.87 kg = (6.87 x 100) = 687 g (wrong because 1 kg is not equal to 100 g)
6.87 kg = (6.87 x 1 000 ) = 6 870 g ( correct because 1 kg is equal to 1 000 g )
2. Mistakes when multiplying
Example :
a) 15 kg 781 g X 6 = 90 kg 4 686 g ( wrong because 4 686 g is not converted to kg)
15 kg 781 g X 6 = 94 kg 686 g ( correct because 4000 g is converted to 4 kg)
VOLUME OF LIQUID
1. Did not arrange decimal points in a vertical line.
Example :
a) 9.8 L + 17.4 L + 239.76 L = 1 317.476 L ( wrong because the decimal point are not arranged)
9.80 L + 17.40 L + 239.76 L = 266 . 96 L (correct because decimal point arranged in vertical line)
2. Mistakes when performing operations involving conversions of units.
Example :
a) 280 ml + 13 l + 1 540 ml = 1 833 l (wrong because did not change ml to l )
0.28 l + 13.00 l + 1.54 l = 14.82 l (correct because change ml to l )
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