JSFiddle - React, Tailwind, and code Playground

HTML

<div class="media-body">
    <div class="menu-tittle">

    </div>
    <div class="quantity">
      <form action="#">
        <div class="pizza-add-sub">
          <input type="text"  class="qtdpedidos" />
        </div>
      </form>
    </div>
    <div class="pizza-price"> <span class="pizza">10.00</span>
    </div>
  </div>
<input type="button" value="SOMAR" id="somar" />
Valor do Pedido: R$<span class="resultado">0.00</span>

JavaScript

$("#somar").click(function(){
  var total = 0;
  var valor= $('.pizza').val());

  $('.qtdpedidos').each(function(){
    var valor = Number($(this).val());
    if (!isNaN(valor)) total += valor;
  });

  total = total - desconto;
  $(".resultado").html(total.toFixed(2));
});