Things You'll Need
Instructions
Select the DSi Shop icon from the main menu screen of the Nintendo DSi. Allow the DSi to connect to the Internet, which may take a few moments. The system will chime when it has connected successfully.
Tap the "Start Shopping" button near the bottom of the screen. From here, select the "DSiWare" button at the top of the screen. This brings you to a virtual online store featuring games and applications.
Select DSiWare in the 200-point category, the button on the top right.
Browse the list of games and applications until you find the Animal Crossing Calculator or the Mario Calculator. As of 2011, these two video game-themed apps are the only calculators Nintendo offers for the DSi system. Games and apps are listed in alphabetical order; scroll through pages of the list by clicking the arrow at the bottom right-hand corner of the screen or the "Back" button in the lower left.
Click on your choice of the Animal Crossing Calculator or Mario Calculator and select "Download." Confirm the download; this deducts 200 Nintendo Points from your account. Allow the DSi to download the calculator app, which takes about five minutes.
Access your new calculator by clicking its icon on the DSi's main menu.