About NumWiz (Free)
The free version of this app includes a well designed scientific calculator, along with a converter that allows you to convert angle, area, currency, energy, length, power, pressure, speed, temperature, time, volume and weight. Get the full version for a range of additional functions and features.
The full version gives the ability to carry out calculations in the following areas: composite numbers, factors, fractions, hcf (highest common factor), lcm (lowest common multiple), mean, median, mode, multiples, number bases, percentage, prime factorization, prime numbers, roman numerals, set notation, area, chi-square distribution, correlation coefficient, density, force, molar mass (molecular weight), perimeter, power, pythagoras' theorem, quadratic equation, standard deviation, standard error, variance, velocity, volume and z-score probability.
It also includes a stopwatch, a timer with optional alarm settings, a password generator, and a GMT display.
In addition, the app has awesome features, such as the ability to read answers aloud.