If you are telling us to revise the sentence, one error is that there is a double negative. 'not' and 'un' would cancel each other, and the revised sentence 'I wouldn't say he's the nicest guy around, but I've seen him behave kindly before.'
I would go with the first the 3. Placing the telescope on the tripod. was chosen by the astronomy club
it is non-fiction because this is something that can happen or did happen
<span>As periods in mathematics we call groupings of large numbers (three-digits) usually separated by comma or space.
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In this particular case we got two periods: 913 and 256.
Digits 913 are in the thousands period, while 256 in the units period.