This is a nice website. It has a collection of applets that range from middle school to college level math.

This website has applets for calculus. The applets are divided in five parts: 1) Exponential functions applets, 2)Limits applets, 3)the derivative and tangent lines applets, 4)tangent lines applets, and 5)differential equations applets.

This website has many advanced and lower level math applets including calculators and data analysis

This website has a collection of 279 math applets for middle school math, trigonometry, calculus, vectors, complex numbers, conics, and miscellaneous.

This website has applets for arithmetic, Elementary Algebra, plane geometry, trigonometry, vector analysis, analysis, and complex numbers