HP-30S Scientific Calculator

[watchmaker]

I've got an HP-30S with Version 03! S/N CN0024 (very early?)

1 ab/c 110 -> 0/1 :-D
2 + 1e-9 - 2 -> 1e-09
sin 3.14159265358 -> 9.793238461e-12
sin(3.1415926535+7391741495627E-23)*1E17-1587582 -> 3.504446358e-01
sin(3.1415926535+7391741495628E-23)*1E17-1587582 -> 3.504438966e-01 :-O

Quote:Part of the reason that the HP-30S returns the exact answer of 9 for the forensics test is that the HP-30S takes the liberty of rounding results to integers that are in very close proximity, which provides answers that are reassuring to novice users.

Very likely! Check Citizen SRP-280 and SRP-285II (other models from the same Kinpo series). The 280 gives approx. 5.2e-11 in the forensics test, the 285II (and all later Citizen models) gives 0.
Note, SRP-285 (without II!) is 14-digit decimal, not binary. TI models are also decimal.

Quote:Key in 1 [a b/c] 110 to put in 1/110 as a fraction via the [a b/c] key. The result is: 0/1. Or calculate 1/10-1/11 in fractional form, the result is 0/1

Citizen models (280, 285, 285II, 300) and TI-34II (also a similar Kinpo model!) do this fine. Maybe it's a specific firmware bug in HP-30 v. 03.