Answer:
348000
Step-by-step explanation:
The place you want to round to is the thousands place. The place to the right of that is the hundreds place. If the digit in the hundreds place is 5 or more (and it is), then the rounded number will have 1 added to its thousands digit.
After making that adjustment (if necessary), all digits to the right (hundreds, tens, ones, and so on) will be set to zero.
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<em>Comment on rounding</em>
Various rounding schemes are in use. The one described above is the one usually taught in school. In real life, it has the disadvantage that it can add a bias to a set of numbers, making their total come out higher than desired. In order to counter that, a "round to even" rule is sometimes used.
In this problem, that would mean the thousands digit would only be changed on the condition it would be changed to an even digit. (Here, that rule would give the same result. The number 346500 would be rounded down to 346000, for example.)
Various spreadsheets and computer programs implement different rounding schemes, depending on the application and the amount of bias that is tolerable. So, you may run across one that seems to be "wrong" according to what you learned in school.
