<html>
<head>
<script>
let input = document.getElementById("Text1")
let addOn = 12 //1. addOn = Number
let splitToArr = input.split(' ') //2. split string into Array
let doMathOnArr = splitToArr.map((i)=>{ //3. Map the array
return parseFloat(i) + addOn //3. Parse each element & add addOn
})
let result = doMathOnArr.join(' ') //4. join back together into a String
</script>
</head>
<body>
<input id="Text1" type="text" value="" />
<button type="button" id="myBtn" onclick="document.write(result);">Run</button>
</body>
</html>