To achieve this, you can use a custom TextWatcher to automatically insert line breaks after the + symbol when the user types a mathematical expression. Below is a step-by-step guide on how to implement this:

1. Create a Custom TextWatcher You need to create a custom TextWatcher
   that monitors the text input and inserts a line break (n) after
   each + symbol.

fun setupEditTextWithLineBreaks(editText: EditText) {
    editText.addTextChangedListener(object : TextWatcher {
        private var isUpdating = false

        override fun beforeTextChanged(s: CharSequence, start: Int, count: Int, after: Int) {}

        override fun onTextChanged(s: CharSequence, start: Int, before: Int, count: Int) {}

        override fun afterTextChanged(s: Editable) {
            if (isUpdating) return

            isUpdating = true

            val originalText = s.toString()
            val newText = addLineBreaksAfterPlus(originalText)

            if (newText != originalText) {
                editText.setText(newText)
                editText.setSelection(newText.length)
            }

            isUpdating = false
        }

        private fun addLineBreaksAfterPlus(text: String): String {
            // Insert line breaks after each '+' sign if not already followed by a newline
            return text.replace("+", "+n")
                .replace("nn", "n") // Avoid double line breaks
        }
    })
}