# Help with new calculator selection (button choices)

• xrayvision
xrayvision
I need a new calculator. I always wondered what the M buttons on a calculator were for, and today I finally got around to Googling for it. Pretty cool.

While watching videos explaining various calculator buttons, I found that some calculators have a 2nd button and a format button where you can set it to AOS and it gives you the answer to the problem using the order of operations, so no M buttons needed. So, it seems to me that the latter type of calculator does what calculators with M buttons do, is that correct? Just wondering if one is more useful than the other when needing to do problems like the following: 6x3 - 2x7 + 15÷5 or 1000 ÷ 1.07 to the 4th power.

Not a very expensive life decision, but I want to make sure I get the best type of calculator. I don't do anything too complicated, just basic record keeping (usually). I've got two desktop calculators picked out, one with each type of set of buttons.

Last edited by a moderator:
RPN FOREVER!!!

gmax137, berkeman, jtbell and 2 others
Frabjous said:
RPN FOREVER!!!
I believe that would be "RPN !!! FOREVER".

Frabjous
I believe that would be "RPN !!! FOREVER".
After reading my OP, would you believe that I get that joke?

xrayvision said:
like the following: 6x3 - 2x7 + 15÷5
In RPN: 6 3 x 2 7 * - 15 + 5 ÷
xrayvision said:
1000 ÷ 1.07 to the 4th power.
The wording of this is ambiguous.
Do you mean this ...
$$\left( \frac {1000}{1.07}\right)^4$$
or this ...
$$\frac{1000}{1.07^4}$$
xrayvision said:
I don't do anything too complicated, just basic record keeping (usually).
If all you're doing is basic record keeping, you probably don't need anything much more complicated than what used to be called a "four banger," a calculator capable of doing addition, subtraction, multiplication, and division.

Mark44 said:
or this ...
The latter.

Mark44 said:
If all you're doing is basic record keeping, you probably don't need anything much more complicated than what used to be called a "four banger,"
Again, I'm also looking for one with either the memory keys or the 2nd button and a format button and wondering if one were more useful than another. I couldn't find any that had both and were also desktop models (big buttons, big screen).

Actually, I couldn't figure out how to do 1000 ÷ 1.07^4 with just memory buttons.

xrayvision said:
Actually, I couldn't figure out how to do 1000 ÷ 1.07^4 with just memory buttons.
Here are the key presses on my Casio fx 260.
1.07 ##x^y## 4 = ##X \to M## 1000 ÷ MR =
Result is 762.895212
On my calculator, to use the ##X \to M## button I have to first press the SHIFT key.

Calculators with memory buttons usually have a pair of keys for parentheses. On my calculator these are shown as [(--- and ---)].
The calculation above can be done like this:
1000 ÷ ( 1.07 ##x^y## 4 ) =
Result is the same as before.

xrayvision said:
Again, I'm also looking for one with either the memory keys or the 2nd button and a format button
You mentioned a format button in post #1 and something about AOS, but I don't know what AOS is short for. As mentioned by others, a different kind of calculator uses RPN (reverse Polish notation). The most prominent company that produces RPN calculators is HP (Hewlett Packard). These calculators typically have an Enter key but no = key. Possibly other calculators do calculations using RPN but I don't know of any and haven't bothered to search for them.

BTW, you shouldn't lose a lot of sleep agonizing over which calculator to buy. They are very inexpensive. This one goes for \$9.49 on Amazon. This is the one I use most. Mine looks almost identical to this except the two blue keys in the picture are red on mine. I like this model because it's solar powered so you never have to change batteries (unless there's a small lithium battery inside -- I've never opened it up).
If all you do is record keeping, this might be overkill.

xrayvision said:
Not a very expensive life decision, but I want to make sure I get the best type of calculator.
Frabjous said:
RPN FOREVER!!!
Mark44 said:
They are very inexpensive.
Just a reminder that there is a free app for the HP-42 RPN calculator. I learned RPN back in undergrad ("Wait, where is the equal sign?!"), and have preferred it ever since.

The free software is available for phones and for personal computers:

https://thomasokken.com/free42/

Mark44 said:
Here are the key presses on my Casio fx 260.
1.07 ##x^y## 4 = ##X \to M## 1000 ÷ MR =
Result is 762.895212
On my calculator, to use the ##X \to M## button I have to first press the SHIFT key.
Mark44 said:
Calculators with memory buttons usually have a pair of keys for parentheses. On my calculator these are shown as [(--- and ---)].
The calculation above can be done like this:
1000 ÷ ( 1.07 xy 4 ) =
Result is the same as before.
Now that's more my speed! So, for these kind of problems, the M keys are redundant? I like the ease of the parentheses keys.
Mark44 said:
You mentioned a format button in post #1 and something about AOS, but I don't know what AOS is short for.
I was following a YouTube video titled "Learn to use the financial calculator in under 7 minutes!" The guy in the video uses a Texas Instruments BA II Plus Financial Calculator. AOS is short for Algebraic Operating System. With the 2nd button and the format button you can change it from solving in a chain to the order of operations.
Mark44 said:
BTW, you shouldn't lose a lot of sleep agonizing over which calculator to buy.
I'm not. I actually have a couple of scientific calculators, but I wanted a desktop model with bigger buttons and bigger screen. I was considering the Sharp VX2128V and the Casio DJ-120DPLUS-W-EP (I like the switches where you can choose how many decimals to round to) but now I might look for a model with parentheses. I also like the Sharp EL-1901 Paperless Printing Calculator so I can check my inputs for mistakes.

• General Math
Replies
1
Views
346
• Mechanical Engineering
Replies
21
Views
1K
• General Discussion
Replies
7
Views
917
Replies
6
Views
992
• Introductory Physics Homework Help
Replies
4
Views
430
• Mechanical Engineering
Replies
7
Views
909
• General Math
Replies
6
Views
1K
• Mechanical Engineering
Replies
21
Views
3K
• Set Theory, Logic, Probability, Statistics
Replies
7
Views
1K
• Introductory Physics Homework Help
Replies
6
Views
1K