A stick has a length of 12.132 cm and another stick has a length of 12.4 cm.
If the two sticks are placed end to end , what is their total length ?

Explanation

(a) Let lengths of the sticks are named as `l_(1)= 12.132cm, l_(2)= 12.4cm`
Here `l_(2)` has one decimal place and `l_(1)` has to be rounded off to have only two decimal places
`l_(1) + l_(2) = 12.13 + 12.4= 24.53`
This is to be rounded off to have one decimal place only
`therefore` The total length is 24.5cm
(b) `l_(1) = 12.132, l_(2) = 12.4`
`l_(1)-l_(2) = 12.4- 12.132`
Here 12.4 has only decimal place and hence 12.132 shoudl have only two decimal places.
`therefore l_(1)-l_(2)= 12.4-12.13= 0.27`
This should be rouned off to have only one decimal place
`therefore l_(1)-l_(2)= 0.3`
Hence difference of their lengths is 0.3cm