J-Calculator lets you add little “calculator” buttons next to applicable fields throughout your APP, as shown here. Or, it can simply be used as a “normal” calculator.
When the calculator is used in conjunction with input fields (using the calculator buttons, as shown), the values in the fields are passed to the calculator as it opens, and can be returned to the fields as the calculator closes.
This provides a very convenient way for your users to update numeric fields using a calculator tool, as they can click on the calculator buttons, manipulate the field value using the calculator, then save their answers back into the fields.
Our clients love this tool, I’m sure yours will as well.