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Simply touch the answer to store it and touch the stored answer to use it in an expression. diese App has four tabs that select four different calculators each with its own color.  Plot graphs with a single touch! diese App plots 2D and 3D functions using the x, y and θ variables.  diese App is a calculator like no other! diese App solves expressions as you type and features an innovative memory system to store and recall answers.  I also use it while shopping and can add the price of my shopping list and calculate what things cost. I love this calculator". "This app is great.  When you use the x, y and θ variables in an equation the answer will say Touch to Plot.  Its 3D graphing capability is great - quick, easy (it sets nice bounds on the z axis so you can see things clearly), and helpful for visualizing my Multivariable Calculus homework".  Having the answer appear as you enter numbers will be the future of all calculators".  Plot functions using the x variable.  Plot 3D functions by using the x and y variables.  It easily graphs functions on the xy plane, and adding T as a variable to make the graph move is so fun.  Plot polar equations using the θ variable.  "Having multiple calculators that you can use your calculations in is really a cool function.  I love having four separate units which I can use in each other and the plotting is easy as pi".  Graph multiple functions by separating each equation with a comma.  Prompt updates, excellent controls, and a ton of features make it the best calculator I have used.  "This is a great calculator, aesthetically and functionally.