JSFiddle - React, Tailwind, and code Playground

HTML

<span>number to buy</span>
<input type="text" value="1" id="factor" />   
<p>    $<span>175.00</span> YR 1 </p>
<p>    $<span>187.50</span> YR 2</p>
<p>    $<span>212.50</span> YR 3</p>
<p>    $<span>225.00</span> YR 4</p>
<p>    $<span>237.50</span> YR 5</p>

JavaScript

$('p span').each(function(){
    $(this).data('factor',$(this).text());
})
    $('#factor').keyup(function(){
        var factor = this.value;
        $('p span').each(function(){
    $(this).text(function(){
        return $(this).data('factor') * factor;
    });
        })
    })