Odd Number (1): 2n₁+1
Odd Number (2): 2n₂+1
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(2n₁+1)(2n₂+1)
= 4n₁n₂ + 2n₁ + 2n₂ + 1
= 2(2n₁n₂ + n₁ + n₂) + 1
Call (2n₁n₂ + n₁ + n₂) a number... Therefore...
= 2n+1 (which must be odd as odd numbers are represented as thus)
*Note that a natural number multiplied by a natural number always produces a whole or natural number. (n) stands for a natural number and furthermore, a natural number added to a natural number produces a natural number. Odd numbers are represented using the expression 2n+1.
