MathTasks2

Math tasks is an application which can perform various mathematical calculations not conveniently done by calculators if at all. It can compute the highest common factor of a list of integers. least common multiple (lowest common divisor) of a list of integers, whether an integer is prime, prime factorization, area of a (convex) polygon, combination and permutation counts, conversion between number bases, area and circumference of a circle/ellipse, distance between two points in a plane or in space, linear regression formulae, and factorial of an integer. More may be added by popular request.
This application has been tested for Android 2.2 and should run on later versions as well..