#### Answer

(i) 12.7
(ii) 12.2
(iii) 18.4
(iv) 18.4
(v) 24.8
(vi) 18.4

#### Work Step by Step

(i) The digit after the 3rd significant digit is 9. This is greater than 5 ,so we round the previous digit up from 6 to 7.
(ii) The digit after the 3rd significant digit is 4. This is less than 5, so we round the previous digit down, and it remains 2.
(iii) The digit after the 3rd significant digit is 5, and no nonzero digits follow. Round towards the even number: 3 becomes 4.
(iv) The digit after the 3rd significant digit is 5, and no nonzero digits follow. Round towards the even number: the 4 remains a 4.
(v) The digit after the 3rd significant digit is 5, and nonzero digits follow. Round up: 7 becomes 8.
(vi) The digit after the 3rd significant digit is 5, and nonzero digits follow. Round up: 3 becomes 4.