This is a fully functional calculator which makes use of the new scoreboard feature in version 220.127.116.11 (Minecraft beta). It’s really an insane calculator which you can use to calculate any numbers from -2147483647 to 2147483647 and everything are made with just command blocks. A “no mod” is a command block creation adding non-existing mechanics to the game (e.g. new items or features) without the player needing to install a mod or an add-on.
Start out by using the buttons on the left and right side to select the first two numbers.
Then use any of the mathematical symbols to calculate the equation.