Question

Convert into decimals and subtract.
(i) 33 rupees 99 paise from 66 rupees 1 paise
(ii) 101 m 50 cm from 102 m 5 cm
(iii) 6 km 10 m from 16 km 100 m
(iv) 15 kg 656 g from 15 kg 744 g

Answer 1

Hint: For the part (i) of the question use the relation 0.01 Rs. = 1 paise to convert both the quantities into decimals and perform the subtraction to get the answer. For parts (ii) and (iii) use the relations 0.01 m = 1 cm and 0.001 km = 1 m respectively while for the part (iv) use the relation 0.001 kg = 1 g to convert into decimals.

Complete step by step answer:
(i) Here we have to subtract 33 rupees 99 paise from 66 rupees 1 paisa but first we need to convert both the units into decimals. Now, we know that 1 Rs. = 100 paise, so 1 paise = 0.01 rupees, therefore we can write: -
$\Rightarrow $ 33 rupees 99 paise = 33 rupees + 0.99 rupees = 33.99 rupees
$\Rightarrow $ 66 rupees 1 paise = 66 rupees + 0.01 rupees = 66.01 rupees
Subtracting 33.99 rupees from 66.01 rupees we get,
$\therefore $ 66.01 rupees – 33.99 rupees = 32.02 rupees
(ii) Here we have to subtract 101 m 50 cm from 102 m 5 cm but first we need to convert both the units into decimals. Now, we know that 1 m = 100 cm, so 1 cm= 0.01 m, therefore we can write: -
$\Rightarrow $ 101 m 50 cm = 101 m + 0.50 m = 101.50 m
$\Rightarrow $ 102 m 5 cm = 102 m + 0.05 cm = 102.05 m
Subtracting 101.50 m from 102.05 m we get,
$\therefore $ 102.05 m – 101.50 m = 0.55 m
(iii) Here we have to subtract 6 km 10 m from 16 km 100 m but first we need to convert both the units into decimals. Now, we know that 1 km = 1000 m, so 1 m= 0.001 km, therefore we can write: -
$\Rightarrow $ 6 km 10 m = 6 km + 0.010 km = 6.010 km
$\Rightarrow $ 16 km 100 m = 16 km + 0.100 km = 16.100 km
Subtracting 6.010 km from 16.100 km we get,
$\therefore $ 16.100 km – 6.010 km = 10.090 km
(iv) Here we have to subtract 15 kg 656 g from 15 kg 744 g but first we need to convert both the units into decimals. Now, we know that 1 kg = 1000 g, so 1 g = 0.001 kg, therefore we can write: -
$\Rightarrow $ 15 kg 656 g = 6 kg + 0.656 kg = 15.656 kg
$\Rightarrow $ 15 kg 744 g = 15 kg + 0.744 kg = 15.744 kg
Subtracting 15.656 kg from 15.744 kg we get,
$\therefore $ 15.744 kg – 15.656 kg = 0.088 kg

Note: You must remember all the conversion relations of units used to measure the same physical quantity otherwise it will be difficult to solve the question. In the above question, do not convert the bigger unit into the smaller one because we have to write the decimal form which is possible only when we convert the smaller unit into the bigger one. Always remember that arithmetic operations are performed on physical quantities with similar units.