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Problem #66 · October 1, 2026

Natural numbers

How many natural numbers are there between the numbers 3737 and 8181 (not counting these numbers themselves)?
  1. A4242
  2. B4343
  3. C4444
  4. D4545
  5. E4646

WORKED EXAMPLE

Solution

The count of natural numbers between aa and bb (excluding the endpoints) is found by the formula b−a−1b - a - 1. Thus, there are 81−37−1=4381 - 37 - 1 = 43 numbers: they are the numbers 38,39,…,8038, 39, \ldots, 80.
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