CrunchJr Computational Stories
(Screen Shots)

This page presents a series of samples of CrunchJr uses.  Most are common computational problems which are solved with CrunchJr on an iPhone, iPad, or iPod/Touch.  Three of the samples are in Quick–mode (under the [MiniApps] tab), six are in PowerUser–mode (under the [Crunch] tab), and the first screen and the last two are just general information.  Quick–mode is very popular with users (simpler interface, less typing), but PowerUser–mode is much more powerful.  Most computational problems can be solved in either mode, but PowerUser–mode provides variables (with one or more values for each), can save the results for later use, and provides for User-defined functions (among other advantages).  The examples use a Storyboard format – with a short description and set of screen shots.  A simple navigation scheme allows you to view selected samples in any order.

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Initial Screens – a peek at the first screens a user will see.



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MiniApp:  Body Mass Index (BMI) – a measure of weight for height and its implications.  Consider a 5' 10½" male weighing 170 pounds.



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Crunch:  Body Mass Index (BMI) – investigate different weights.  This computation zeroes in on the weight a 5' 10½" male needs to get down to in order to get into the Normal Range.



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Crunch:  A simple expression with 1 variable – show how to use a simple expression.



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Crunch:  A simple equation with 2 variables – show how to use a simple equation.  An equation takes the form  var  =  expression,  where the expression can use any variables except var.  After the evaluations, all the values for var are kept in the Store, where they are availble for later use.



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MiniApp:  Solve 3 equations in 3 unknowns – using Quick–mode we can quickly solve a set of equations (PowerUser–mode could be just as easily used).  Consider these three equations:



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Crunch:  Mortgage payoff strategy – consider a partly paid off mortgage with an outstanding balance or $195,600, with a 5.2% loan and a monthly mortgage payment of $1,106.  What impact would paying a little more with each monthly payment have on total out-of-pocket cost for the house?  Look at 4 values for the extra payment ($50, 100, 150, 200).



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MiniApp:  Complex Division – arithmetic with complex numbers.



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Crunch:  approximate numerical integration – integrate the expression: x² sin(x)  from x = 1.7 to 1.9



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Crunch:  Error detection CrunchJr catches errors in four places: during typing, during semantic analysis, during variable value determination, and at run-time (when the expression is being evaluated).  This section gives several examples of errors and their associated messages.  Note that the error screens are bright yellow (although this color is user-settable).






  • Screens 11,12 – mismatched parentheses are detected during semantic analysis.
  • Screen 13 – an illegal sequence is detected during typing



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    Search – samples of the CrunchJr Search capability, which employs a simple, single-keyword search.  Results are tabulated on the fly beginning with the third character.  There are four collections of information which can be searched: Functions, Constants, Screens, and (All 3).



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    A selection of popular and esoteric screens – this section contains a random set of Screens chosen from the 140+ available under the [Info] tab. Note that many of these screens are larger than 1 page.




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