get sum total by using foreach

I am trying to get a total by using the foreach in javascript but failing somehow…it just lists the values rather than give me total figure`

const finances = [
    ["Jan", 867884],
    ["Feb", 984655],
    ["Mar", 322013],
    ["Apr", -69417],
    ["May", 310503],
];

let sum2 = 0;
for (let i = 0; i < finances.length - 1; i++) {
  let monthDiff = finances[i][1] - finances[i + 1][1];
  // console.log(monthDiff)
//   console.log(typeof(monthDiff))
  const newArray = [monthDiff];
  // console.log(newArray)
  newArray.forEach((item) => {
    sum2 += item; 
    console.log(sum2); //listing values not giving me a total why?
  });
}