how do I add the variables together - variables

Question

I am really new at this probably can tell. I am trying to add my variables together and display on site. So i cannot get protein 1 and protein 2 added together. How can i get them to add. I would like the user to up arrow till he gets to his right amount of proteins for steak and for chicken. Then I would like to add the total number of proteins, fats, calories for steak and chicken
<h5>Chicken Breast
<button id="up1">+</button>
<button id="down1">-</button>
<b id= "chounces"></b>
</h5>
<h5>Flank Steak
<button id="up2">+</button>
<button id="down2">-</button>
<b id= "stkounces"></b>
</h5>
function updateQuantity(displayQuantity) {
let quantity1 = document.querySelector('#chounces')
quantity1.innerHTML = displayQuantity
}
// Start chicken variables at 0 since product is in cart
let quantity1 = 0
let protein1 =0
let fats1 =0
let calories1 = 0
// Buttons
const quantUp = document.querySelector('#up1')
// add event listener to increase quantity
quantUp.addEventListener('click', function(){
quantity1++
protein1= quantity1 * 6
fats1 = quantity1 * .35
calories1= 31 * quantity1
updateQuantity(`ounces: ${quantity1}, protein: ${protein1}, fats ${fats1}, calories ${calories1}`)
})
//steak
function updateQuantity2(displayQuantity2) {
let quantity2 = document.querySelector('#stkounces')
quantity2.innerHTML = displayQuantity2
}
// Start steak variables at 0 since product is in cart
let quantity2 = 0
let protein2 =0
let fats2 =0
let calories2 = 0
// Buttons
const quantUp2 = document.querySelector('#up2')
// add event listener to increase quantity
quantUp2.addEventListener('click', function(){
quantity2++
protein2= quantity1 * 6
fats2 = quantity1 * .35
calories2= 31 * quantity1
updateQuantity2 (`ounces: ${quantity2}, protein: ${protein2}, fats ${fats2}, calories ${calories1}`)
})