JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="one">
<input type="text" id="two">
<button type="button" onclick="findTen()">compute</button>
   
<b id="output"></b>

JavaScript

findTen = function()  {
    var a = document.getElementById("one").value;
    var b = document.getElementById("two").value;
    var doTheMath = Number(a) + Number(b);
    var c = false;

    if ( a == 10 || b == 10)  {
        //alert("true");
        c = true;
    }
    else if (doTheMath == 10 ) {
        //alert("true");
        c = true;
    }
    else {
        //alert(a + ' ' +  b + ' ' + doTheMath);
        c = false;
    }
    document.getElementById("output").innerHTML = c;
}