FDP Strategy Guide Ch. 2, Problem 1

[KelseyR968]

Here's the question:

In the decimal, 2.4d7, d represents a digit from 0 to 9. If the value of the decimal rounded to the nearest tenth is less than 2.5, what are the possible values of d?

The solution provided is {0, 1, 2, 3, 4}, but if d= 4 then wouldn't 2.447 round up to 2.5? In that case, to arrive at a number less than 2.5, d would have to be {0, 1, 2, 3}. Am I missing something?

[RonPurewal]

if you round 2.447 to the nearest tenth, you get 2.4.

(analogy: what is 447 rounded to the nearest hundred? it's 400, not 500.)

__

[RonPurewal]

what you MIGHT be doing, here, is first rounding to the nearest hundredth (giving 2.45), and THEN rounding to the nearest tenth.
if you're doing that ... well, don't do that. (:
just follow the given directions.
(in the same way, you wouldn't first round 447 to 450 and then round to the nearest hundred -- you'd just round it directly to the nearest hundred.)