Let's look at some simple questions:

Question 1:
James can make $200 per day, what would be his annual income ( He works 5 days a week, 48 weeks per year) ?

This is easy, just enter an expression as this in Xmart Calculator: 200 x 5 x 48

Question 2:
How many times of tapping a button to calculate his annual income?

8 times on a normal calculator, 7 times on Xmart Calculator (you don't need to tap the '=' button).

Question 3:
What if his day rate is $320, $400, $500...?

Well, very similar:
320 x 5 x 48;
400 x 5 x 48;
500 x 5 x 48...

What's the problem? With a normal calculator, we have to enter the same buttons 'x 5 x 48' very time when the only value changes is just the day rate.

Is there any way to just enter the day rate and the result will update automatically?

With Xmart Calculator, YES! You can define a Algebra function like this:

"IncomeByDay(X) = X x 5 x 48"

Then you can just select the function and enter the value for 'X' and the result will update straight away!

To get James annual income, you just need to tap buttons 4 times.

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End of questions
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Xmart Calculator is appreciated as an intelligent, programmable and expandable calculator based on text expression.

In addition to most of the common and scientific functions, users can also define personal functions.

All calculations are step-by-step traceable.

**Quick start:

* There is no '=' button in this calculator app, it will calculate and show result as soon as the expression is updated.
* Swipe up/down to hide/show the history records.
* Swipe left and right to hide/show the scientific/math functions.

**Main feature:

* Custom functions: user can define any algebra functions with up to 9 parameters.
* Use a custom function in the main expression or play with it separately.
* Calculate and show result instantly when the input is updated.
* Most common scientific & math functions are included.
* Save calculation to history
* Review & Recall history results or expressions
* Name/label a history item meaningfully
* Record and show step by step details of the calculation
* Share history with friends
* Fast mortgage calculator is included


**Additional features

* Support Apple Watch & iMessage
* Auto save: turn ON/OFF or set a custom timer for saving results automatically
* Colours, layouts and fonts are configurable, you can design your own calculator.
* Turn ON/OFF button sounds.
* Select button sound from 6 different options