JSFiddle - React, Tailwind, and code Playground

HTML

Saldo 1:<div id="debit">0.00</div>
Saldo 2<div id="credit">0.00</div>
TOTAL:<div id="total">0.00</div>
<br><br>

Valor X:<div id="valX">0.00</div>
<input type="number" id="txt-valX" placeholder="vai add ao saldo 2">
<button onclick="addX()" id="bt0">OK</button><br>
Valor Y:<div id="valY">0.00</div>
<input type="number" id="txt-valY" placeholder="vai add ao saldo 1">
<button onclick="addY()" id="bt1">OK</button><br>
Valor Z:<div id="valZ">0.00</div>
<input type="number" id="txt-valZ" placeholder="vai add ao saldo 1">
<button onclick="addZ()" id="bt1">OK</button>

JavaScript

var total = window.document.getElementById('total')
    var debit = window.document.getElementById('debit')
    var credit = window.document.getElementById('credit')
    var somatotal = 0
    var somadebit = 0
    var somacredit = 0

    var valX = window.document.getElementById('valX')
    var valY = window.document.getElementById('valY')
    var valZ = window.document.getElementById('valZ')
    var somavalX = 0
    var somavalY = 0
    var somavalZ = 0

function addX() {
    var txtval = window.document.getElementById('txt-valX')
    var val = Number(txtval.value)
    var totalres = somatotal += val
    var totalval = somacredit += val
    total.innerText = totalres.toFixed(2)
    credit.innerText = totalval.toFixed(2)
    var valWay = somavalX += val
    valX.innerText = valWay.toFixed(2)
}
function addY() {
    var txtval = window.document.getElementById('txt-valY')
    var val = Number(txtval.value)
    var totalres = somatotal += val
    var totalval = somadebit += val
    total.innerText = totalres.toFixed(2)
    debit.innerText = totalval.toFixed(2)
    var valWay = somavalY += val
    valY.innerText = valWay.toFixed(2)
}
function addZ() {
    var txtval = window.document.getElementById('txt-valZ')
    var val = Number(txtval.value)
    var totalres = somatotal += val
    var totalval = somadebit += val
    total.innerText = totalres.toFixed(2)
    debit.innerText = totalval.toFixed(2)
    var valWay = somaY += val
    valY.innerText = valWay.toFixed(2)
}