Formula Editor app for iPhone and iPad

with this app, you can create your own formula to use, there are 4 vars can be used in this app. for example, if you want to create a formula for rectangular area, you can do as below:
Creating a formula:
1. create a new formula by click + on tool bar.
2. input formula name, here we input "rectangular area".
3. input formula, here we should input x0*x1.
4. we need two vars here, so click + to add one more var.
5. input var for x0, here we use "width".
6. input var for x1, here we use "height".
7. click save on tool bar, it is done.
8. go back to main page, you will be able to see there is a formula with name rectangular area there.
Calculation
1. click on formula name, it brings you to calculation page.
2. input the vars, should all in number.
3. click the first button on tool bar, you should get result.
Edit
If you find your formula has error, you can edit the formula to modify it.
1. go to formula calculation page, click the edit button on tool bar.
2. edit the formula as you want.
3. there is a function list can be used into your formula, just click the function list, on function list, click the function name, then that function will be input into formula filed.
Upload
If you want to upload the formula, you can upload the formula, other people may use it, or if you can download it when you re-install this app. notice, once the formula has been uploaded, you can not edit it any more, so be careful to do that. but you still can edit it locally.
Search
Before you create a new formula, it is better to do a searching first, there might has one already.
1. go to search page, input keyword.
2. if you find the formula you are interested, click it.
3. app will bring you to formula detail page.
4. if this is what you want, save it.
5. go to main page, the formula you just saved should be there.
Delete
If you find you do not need a formula anymore, just click it on right information button to delete the formula on formula list page.