(2) 16 2 = 256, and the original formula was about 16. Take 16, 1 and it is 259, so 16.0 is close.
(1) The root number three is about 1.72 minus 1 divided by 2 is about 0.36 less than 1/2.
(2) Square 3.85, that is, 14, less than 15.