The calculator is used to test your eyesight and recognize the difference in color shades. After clicking on the first lighter field, the calculator will change colors and the countdown will begin. Each test takes 15 seconds. Search for a lighter field and click on it. Each subsequent test is more difficult. The test will be aborted if you do not give the correct answer within 15 seconds or if you make a wrong choice three times.

The calculator helps you to calculate the present value of money (PV) and the future value of money (FV) in time.

The cone calculator will help you calculate the volume of the cone, the total area of the cone, the side area of the cone, the base area of the cone, the generatrix length and the radius of the cone base, and the volume of the sphere described on the cone.