Arithmetic With Null and Zero
There is little difference between the { } and { 0 } views for
addition, subtraction and multiplication except the difference in views as
either the presence or absence of a value. There is a considerable
difference however, for division.
If, when dividing or multiplying quantities, zero really represents
"nothing at all" then there is literally nothing to operate on
and the result is "null" or nothing, rather than any value. (The
examples below work equally well with 2+0, 3-0, 4/0, etc, I use
"1" for simplicity and consistency).
Using the conventional view of zero { 0 }:
1 + 0 = 1
1 - 0 = 1
1 * 0 = 0
1 / 0 = Infinity
Viewing zero as null { } these may be thought of as:
1 + = 1
1 - = 1
1 * =
1 / =
Which is equivalent to:
1 + = 1
1 - = 1
1 * = 0
1 / = 0 (Note)
Taking the null view, if we interpret zero as null then we also
interpret the null results of multiplication and division as zero, i.e. 1
* 0 = 0 and 1 / 0 = 0. We use null and zero interchangeably.
Division By Zero
Note the variation in the results between the views above: division by
zero.
Interestingly, the old axiom that you "should not divide by
zero" still holds true, not because it arbitrarily avoids infinities
but because there is nothing to divide by and it is the right thing to do.
The null view then gives two differences:
(a) results may be null or "incomplete" reflecting the
absence of a value, and
(b) the result of division by zero is zero or "nothing".
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