Math constructor form

The form layout consists of the following elements:

1. Fields for entering the name and description.

2. A compound string consisting of the following fields:

2.1. Select to input value or enter a string.

2.2. Select to input a value.

2.3. Select to input value or enter a string.

2.4. Button for adding a line.

2.5. Button for deleting a line.

3. A string with a list of operators for grouping strings.

4. A string displaying the generated expression

5. Form submit button.