A stick has a length of 12.132cm and another has a length of 12.4 cm. IF the two sticks are placed end and to what is the total length? IF the two sticks are placed side by side, what is the difference in their lengths?

Explanation

(a) Let lengths of the sticks are named as `l_1 = 12.132 cm, l_2 = 12.4 cm`
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 .
`:.` The total length is 24.5 cm
(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 12.312 should have only two decimal places.
`:. l_1 - l_2 = 12.4 - 12.13 = 0.27`
This should be rounded off to have only one decimal place
`:. l_1 - l_2 = 0.3`
Hence difference of their lenghts is 0.3 cm.