A technician doesn't calculate he compare different ratio.

A technician is not interested in negative results for example -10 or -30 cause he got no use for them.
It cant be -30 trees in the wood or -3 inch thas not exist on the folding rule. He is only interested in positive sum.

The guy that is number one among the greatest mathematics is definitely Mr. Kelvin, to him minus didn't exist only 0 and + . The guy who had swindled the hole world has to be Mr.. Celsius - degrees.

Example 1.
A computer doesn't calculate, it compare long binary numbers  toward each other, it called machine language and  its built by the to must common alternative and/or.

Example 2.
If I should say: I'm 0 years but I'm born -46 years ago its true. But it confuse your brain and makes everything difficult.

Or:
If minus exist then 0 should be something.

An economist is on the other hand calculating, money.
To him minus exist -10 dollars -20.000 dollars not in your wallet but on your account.
You can not have -3 dollars in your wallet.

Assume that the economist was called Mr. Kelvin then poorest guy should have 0 dollars and the rest should have + dollars.