A
mathematician myself, I rely on "rules of Thumb" - If I hold my thumb
up and can see the runway above my orthogonal directed index finger
and, using
the right hand rule, I then know that my hand is not on the right
(correct) engine management tool. After fixing that problem, if the
houses are getting large too fast, I go around or go aground
(depending).
Everything else is just a "feel good" estimate.