It is said that 4a x 4b = 16ab.

Absurd

Imagine a = chairs, and b = tables.
When we multiply chairs by tables (Impossible! You shout, but oh no! Cry mathematicians with great and noble fervour) we somehow get 16 chairtables. Or is it 16 tablechairs? I do not know, lacking the carpentry skills mathematicians possess.

Where did the other chairtables come from? Surely 4chairs x 4tables can equal no more than 8chairtables? Unless there is some unknown chairtable maker in service to mathematicians. But I have not heard of him or her.
So practically 4a+4b = 4ax4b given enough wood.

It is said that 4a-8a = -4a

Absurd

Imagine again our chairs being a. Suddenly we have -4chairs. I have never seen a negative chair, but mathematicians say they exist. Perhaps they are hiding under the negative tables?

Or is it me who is being negative?

Then we have the kicker of them all, 0.
Look there! Shout mathematicians, there are ZERO chairs over there. Why do I feel like the little kid in the emperors new clothes? No, reply I , there is no thing there. And if 0butter = 0chairs then chairs = butter?
No, it all gets quite sticky as we come closer to zero.

Negatives, composite welding, zero... all these bizarre things are thrown about willy nilly and are used to design cars, planes, rocket ships. When they blow up we say it was mechanical failure. But I wonder if perhaps some butter got into the formula somewhere?