Obtaining value and setting new value using one function for different input fields

Using vue, I have five input fields for different categories. I want to pass each input field into one function, manipulate the value, and then assign the updated value to the original input name.

<q-input
    v-model="categoryOne"
    name="categoryOne"
    @change="onSelected($event, categoryOne)"
></q-input>
 <q-input
    v-model="categoryTwo"
    name="categoryTwo"
    @change="onSelected($event, categoryTwo)"
></q-input>


function onSelected(event, category) {
   //how would I take the input of each category and perform an 
   action that updates the original value? For example:

    [categoryOne/categoryTwo] = category + 2.
    }