Slide rules are super cool. Such an easy gift to give the engineer in your life.

I never spent the time to get quick with it, but I could absolutely see it being quicker than a calculator. You’d just have to be aware of the limits to its precision if you were in a field that required it.

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deepspace 5 hours ago | parent [-]

Quicker than an algebraic calculator, maybe, but very few people could get. faster with a slide rule than an ergonomic RPN calculator. like the HP 41 series. And I say that as an enthusiastic and experienced slide rule user, before I switched to a calculator.

One problem with a slide rule is that it only performs operations on normalized mantissas. You have to keep a parallel exponent calculation in your head, and that slows you down. Also, maintaining best precision slows you down.

	▲	litoE 2 hours ago \| parent \| next [-]
		When using a slide rule, keeping track of the number of digits to the left of the decimal point (DLDP) in the result is fairly simple if you know the basic rule: For multiplication, the DLDP in the result is: - the sum of the DLDPs of the multiplicands MINUS 1 if the multiplication is done with the slide sticking out to the right of the ruler's body (for example 2.0 x 3.0 = 6.0). - the sum of the DLDPs of the multiplicands if the multiplication is done with the slide sticking out to the left of the ruler's body (for example 5.0 x 4.0 = 20.0). There's a similar rule for division, but that's left as an exercise for the student.
	▲	ghaff 2 hours ago \| parent \| prev [-]
		I used an HP-41CV for many years. I needed the financial calcs module which I used in place of the dedicated HP financial calculator in grad school. Eventually gav out on me but was a good calculator for a long time. I did keep a slide rule as a backup for exams in college when calculators were still LED but never really used one after a couple of years in high school.