Casio DF-120TE I have the Casio DF-120TE calculator. At the top of the screen it says C1 EXCH and I am unable to input any numbers or other functions. How do I get out of this mode? I was not the last person to use this calculator and I do not know how it got into this mode. Any suggestions are appreciated. Thanks.

The c1, c2, & c3 are for exchange rates. To set the c2 exchange rate press AC. Press the MODE M/EX button till EXCH appears in the display. Press and hold the SET/% button for a few seconds until SET EXCH appears in the screen. Press c2, C2 SET EXCH RATE should be displayed. Enter the desired echange rate. For instance, today, Thai Baht is 32.8677. Once you enter your desired exchange rate, press the SET/% button.

To convert 100 dollars using the exchange rate you set on c2, make sure that EXCH is in the display by toggling the MODE M/EX button. Press AC, enter 100, press c1 then c2. Using 32.8677 as the exchange rate 100 dollars would be 3286.77 THB.

To convert 100 THB to dollars you would enter 100, then press c2 and then c1 yeilding 3.04 dollars.

You can also program a different exchange rate into the C3 button. To convert to that currency, you press c1 then c3. To convert from that currency, you press c3 then c1.

Hope that helps

From CASIO FAQ:


How do change the currency rate?

When you press the [M/EX] key, it toggles between conversion mode and memory mode. You will see "EXCH" on the display when in conversion mode.
C1, C2, and C3 are three conversion rates. C1 is your home country currency, and so it is always set to 1. C2 and C3 are rates for two other countries, which you can change.
For example, if you want to set a conversion rate of $1 to 0.95 euros, here is what you would do (using C1 for US dollars and C2 for euros):
1. Press [AC]
2. Hold [SET/%] for about two seconds until "SET" appears
3. Press [C2] to select currency 2
4. Input the conversion rate (0.95) and then press [SET/%] to store it in memory
You can check the currently set rate at any time by pressing [AC] and then [C2].


How do I perform a currency conversion?

If you want to convert 100 euros to US dollars, you would do the following (assuming you are using C1 for US dollars and C2 for euros):
1. Press [AC]
2. Enter 100 and then press [C2]
3. Press [C1] to convert to dollars
4. To convert back to euros again, press [C2]
You can also perform a currency conversion within a calculation. How much in US dollars would five items selling at 100 euros cost?
1. Press [AC]
2. Enter 5 [×] 100 and then press [C2]
3. Press [C1] [=]

press and hold % button until disply current rate. Then enter newrate and press % agian.

To change tax rate on Casio DR-210TM:
Hit <CA>
Hold <%> for 5 sec until '0' re-appear
Enter 'Tax Rate' and <TAX+>

DOWN LOAD A MANUAL FROM THE FOLLOWING SITE, AT FIRST GLANCE IT LOOKS AS THE
MANUAL IS IN SPANISH, ITS ONLY 3 PAGES INCLUDING ENGLISH.

http://www.usersmanualguide.com/casio/calculators/d-120te_castellano

First press the AC button, then the % (Set) button for 2 seconds (it will display the rate) change it to what you want and press set rate again.

If you don't have an AC button, then press the C/AC button twice.

TRY 3 OVER 4 IE 3 QUARTERS

For the MS-80TE and MS-100TV this suggestion works - with the MODE select the EXCH than hold down the SET button. on the screan SET EXCH will appear, press the C2 /the C1 is by default 1/ and set the rate, press SET again and you are done
Hope i helped !

Found this on the casio site worked fine on my ms-120TE
1. Press [AC]
2. Hold [SET/%] key for about 2 seconds until set and a 0 is displayed
3. Press [TAX+]
4. Input the tax rate
5. Press [SET/%]

this is the link:- http://www.casio.com/support/content/AF64A1AC-193D-4650-A9A9-98BB6FE26CFE