Round off the following numbers as indicated :
(i) `15.654` upto 3 digits `" " (ii) 15 . 75 ` upto 3 digits `" " (iii) 15.654` upto 4 digits `" " (iv) 15.65` upto 3 digits (v) 142667 upto 5 digits (vi) `5.996 xx 10^(5)` upto 3 digits . (vii) `0.7995` upto 1 digit (viii) `2.5946 xx 10^(-4)` upto 2 digits .