1- Photomath
‘Simply point your camera toward a math problem and Photomath will magically show the result with a detailed step-by-step instructions…Photomath supports arithmetics, integers, fractions, decimal numbers, roots, algebraic expressions, linear equations/inequalities, quadratic equations/inequalities, absolute equations/inequalities, systems of equations, logarithms, trigonometry, exponential and logarithmic functions, derivatives and integrals.’
2- Mathway
'From basic algebra to complex calculus, Mathway instantly solves your most difficult math problems - simply type your problem in (or point your camera and snap a pic!) to receive instant free answers.'
3- Zebra Math
‘Zebra Math brings the amazing math learning experience. The levels and tasks help children learn math step by step, which have been proved to be systematic and effective. Enjoy exploring Zebra Math.’
4- MathX
‘MathX brings the power of a graphic and scientific calculator on your iPhone and iPad. It can solve more than 18 operations and gives you step-by-step explanations. It allows you to graph and compare up to seven functions simultaneously.’
5- Desmos Graphing Calculator
'Explore math with Desmos! Plot functions, create tables, add sliders, animate your graphs, and more -- all for free...Using our powerful and blazingly-fast math engine, the calculator can instantly plot any equation, from lines and parabolas up through derivatives and Fourier series. Sliders make it a breeze to demonstrate function transformations. It's intuitive, beautiful math.'
This is an updated version of this post.