Who This Checklist Is For

If you're responsible for buying or managing office calculators for a team – maybe a school, a finance department, or a small engineering firm – you've probably had to deal with someone who somehow corrupted the memory on a Casio fx‑8200AU (or any Casio scientific). You end up spending 20 minutes on the phone trying to talk them through a reset, or worse, they order a replacement because they think it's broken.

This checklist is for anyone who wants to:

  • Clear memory properly on Casio calculators (especially the fx‑8200AU black model)
  • Avoid the 'I broke it' panic that leads to unnecessary replacement orders
  • Save the cost of unnecessary repairs or new units – because every dollar counts when you're managing a procurement budget

I've broken it into four steps. Follow them in order, and you'll have a clean calculator without guessing.

Step 1: Know Which Memory You Need to Clear

This is the step most people skip – and it's where the confusion starts. Casio scientific calculators (fx‑8200AU, fx‑991EX, fx‑CG50, etc.) have multiple memory stores:

  • Variable memory – stores values for A, B, C, X, Y, M, etc.
  • Statistical memory – stores data from STAT mode
  • Setup memory – stores angular unit (Deg/Rad/Gra), number format, display settings
  • Reset memory – some models have a separate 'all clear' that wipes everything including setup

If you only need to clear variables, you don't need a full reset. But if the calculator is acting wonky – wrong answers, weird display – a full memory reset is safer.

(Note to self: I should have documented this years ago. Every time someone says 'it's broken', 80% of the time it's just a memory issue.)

Step 2: Clear Variables on the Casio fx‑8200AU Scientific Calculator Black

For the fx‑8200AU (the black version is the same internally), here's the exact sequence:

  1. Press SHIFT (the yellow button).
  2. Press 9 – this takes you to the CLR (clear) menu.
  3. You'll see three options:
    1: Mem (variables)
    2: Setup
    3: All
  4. Press 1 to select Mem, then press =.
  5. Press = again to confirm. The calculator will show 'Memory Cleared'.

That's it. This clears all variable values (A, B, M, etc.) but keeps your setup settings (like Deg mode).

Important: The fx‑8200AU doesn't have a separate button for 'clear all memory' like some older models. If your model is different, the menu might appear differently.

Step 3: Full Reset (When Variables Aren't Enough)

If the calculator is showing strange behavior – for example, it keeps giving you answers in radians when you need degrees – you need a full reset that clears setup as well.

  1. Press SHIFT then 9 as before.
  2. Select 3 (All).
  3. Press =, then press = again to confirm.
  4. The calculator will reset all settings to factory defaults and clear variables.

One caveat (which I learned the hard way): this also resets the contrast setting. If the screen suddenly looks dim after the reset, don't panic – just press SHIFT + MENU (the SETUP button) and adjust contrast with the ▲/▼ keys.

Honestly, I'm not sure why Casio doesn't include a separate 'reset contrast only' option. My best guess is they assume most users will never need to adjust it.

Step 4: What Most People Forget – Checking the Battery

This step isn't strictly about clearing memory, but it's the #1 cause of 'my calculator won't clear' complaints. If the battery is low, the clear operation might appear to work but the memory won't actually erase completely. You'll see 'Memory Cleared' on the screen, then a minute later the old data comes back.

Quick check: Press SHIFT then 7 (on most models) to see battery indicator. If it shows low, replace the battery (CR2032 for fx‑8200AU). A fresh battery ensures the clear operation actually happens.

From a cost perspective, replacing a battery ($2‑3) beats ordering a new calculator ($30‑80). But I've seen procurement teams spend $200 on rush replacement calculators because no one checked the battery first. That's the kind of waste that makes a cost controller cringe.

Common Mistakes to Avoid

  • Mistake #1: Pressing AC instead of SHIFT+9. The AC (all clear) button only clears the current input line – it doesn't touch stored memory. I've watched people mash AC for 30 seconds thinking it would reset everything. Nope.
  • Mistake #2: Assuming all Casio models use the same sequence. The fx‑991EX uses SHIFT + 9 too, but older models like the fx‑83GT require MODE + 8. Always verify with the model's manual.
  • Mistake #3: Clearing memory unnecessarily. If the calculator is working fine, don't clear it just because 'it's been a while'. I've had users erase stored constants (like conversion factors) that took me hours to calculate. You can't get that time back.

Why This Matters for Your Bottom Line

From the outside, clearing calculator memory looks like a trivial skill. The reality is that poorly managed equipment leads to productivity losses and unnecessary purchases – both of which inflate your TCO (total cost of ownership). In my experience managing office supply budgets over 6 years, I found that 30% of 'urgent calculator replacements' could have been avoided with a simple memory clear and a new battery.

That $30 calculator becomes a $300 problem when you factor in rush shipping, admin time, and disposal fees.

So the next time someone says their Casio calculator is 'broken', try this checklist first. It might save you a repair order, a replacement, and a few dollars that are better spent elsewhere.

(This procedure was accurate as of April 2025. Casio updates firmware occasionally, so verify the sequence for your specific model if it's newer than the fx‑8200AU.)