These calculators use a slightly different procedure compared to other Casio calculators. Up to seven conversion rates can be registered. Each one has a name, such as € -> $. The rate that you specify here would be from the first currency to the second, but conversions can be done in both directions. For example, if you want to set a conversion rate of 1 euro to 0.93 US dollars, here is what you would do (using C1 for euros and C2 for US dollars):
1. Press [AC]
2. Hold [RATE SET/%] for about two seconds until "SET" appears
3. Press [C2] to select currency 2
4. Press [+] repeatedly to select the currency name (such as € -> $)
5. Input the conversion rate (0.93) and then press [RATE SET/%] to store it in memory