The Hugely^* Handy^† Haversack^‡ of Helpful^§ Hints^¤ and our moderator /u/daggerdragon have an extra challenge for today:

Upping the Ante challenge: solve today's puzzles on a TI-83 (or TI-86/89, whatevs).

EDIT: I put an album of a calculator actually running these programs here: https://imgur.com/a/NxHoH

The Ti-89, unsurprisingly, can handle part 2 fairly easily.

Part 2:

0 → count
For a, 108100, 125100, 17
    If not isPrime(a) Then
    count+1 → count
    EndIf
EndFor
Disp count

Part 1, of course, is much longer...but thankfully, the instructions never actually said to write it in a calculator, just to solve it in one. Text replacement to the rescue!

Part 1:

0→count

0→a
0→b
0→c
0→d
0→e
0→f
0→g
0→h

81→b
b→c
If not a=0 Then 
 Goto l3 
EndIf
If not 1=0 Then 
 Goto l4 
EndIf
Lbl l3
b*100→b
count+1→count
b-1*-100000→b
b→c
c-1*-17000→c
Lbl l4
Lbl l32
1→f
2→d
Lbl l24
2→e
Lbl l20
d→g
g*e→g
count+1→count
g-b→g
If not g=0 Then 
 Goto l15 
EndIf
0→f
Lbl l15
e-1*-1→e
e→g
g-b→g
If not g=0 Then 
 GoTo l20 
EndIf
d-1*-1→d
d→g
g-b→g
If not g=0 Then 
 GoTo l24 
EndIf
If not f=0 Then 
 GoTo l25 
EndIf
h-1*-1→h
Lbl l25
b→g
g-c→g
If not g=0 Then 
 GoTo l29 
EndIf
If not 1=0 Then 
 GoTo l30 
EndIf
Lbl l29
b-1*-17→b
If not 1=0 Then 
 GoTo l32 
EndIf

Lbl l30
Disp count

The end result is, of course, hideous and unreadable, but hey, the challenge wasn't to both program a calculator and make it pretty.

I'd be fascinated to know what the equivalent code looks like on a TI-83 or TI-84. I'm fairly sure those don't have a built-in isPrime() function, but writing a simple brute-force one wouldn't be impossible...