Answer:
Unfathomable, perplexing, mystifying, and enigmatic are all words that mean difficult to understand, explain, or identify.
Answer:
the correct answer is all the above
Explanation:
<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.