# Having rounding issues

Tell us what’s happening:
In the Cash Register challenge in JS Algorithms and Data Structures, I’m running into a problem with rounding. In the area of the code commented as //passing change to new array, I’m finding that the arithmetic operations that are happening are leaving me with imperfect results that are leaving me one penny short of my cash register working properly. I’m using Number(variable).toFixed(2) to round the results to two decimal places, but it doesn’t seem to be working. The operation that is being performed in this test case is 76.74 - 20. This leaves me with 56.739999999999995, which throws off all the rest of the calculations. As a proof of concept, if I write:
console.log(Number(76.74 - 20).toFixed(2))
I get 56.74, which is what I want. When the same operation is performed with variables instead of numbers, it doesn’t work. I’m kind of at a loss. Any ideas on what I’m doing wrong?

``````
function checkCashRegister(price, cash, cid) {

//setting up initial variables to work with
let totalInRegister = 0;
cid = cid.reverse();
for (let i = 0; i < cid.length; i++) {
totalInRegister += cid[i][1];
}
let output = {status:'', change: []}
let difference = Number((cash-price).toFixed(2));

//making sure there's enough in the register to perform the transaction
if (difference > totalInRegister) {
output.status = "INSUFFICIENT_FUNDS"
}

//adding a numeric version of each currency to cid
for (let item of cid) {
switch(item[0]) {
case 'PENNY':
item.unshift(0.01);
break;
case 'NICKEL':
item.unshift(0.05);
break;
case 'DIME':
item.unshift(0.1);
break;
case 'QUARTER':
item.unshift(0.25);
break;
case 'ONE':
item.unshift(1);;
break;
case 'FIVE':
item.unshift(5);
break;
case 'TEN':
item.unshift(10);
break;
case 'TWENTY':
item.unshift(20);
break;
case 'ONE HUNDRED':
item.unshift(100);
break;
}
}

//making a new array to pass the change to
let cidCopy = []
for (let i = 0; i < cid.length; i++) {
cidCopy.push([cid[i][1], 0])
}

//passing change to new array
for (let i = 0; i < cid.length; i++) {
while (difference >= cid[i][0] && cid[i][0] <= cid[i][2]) {
cidCopy[i][1] += cid[i][0];
cid[i][2] -= cid[i][0];
difference -= (Number(cid[i][0]).toFixed(2));
//console.log so I can see what's happening;
console.log(difference)
}
}

//making an array to populate with final change and pass to output
let toPass = [];
for (let i = 0; i < cidCopy.length; i++) {
if (cidCopy[i][1] > 0) {
toPass.push(cidCopy[i]);
}
}

//passing change to output
output.change = toPass;

//getting the total in toPass for comparison against register
let toPassTotal = 0
for (let i = 0; i < toPass.length; i++) {
toPassTotal += toPass[i][1];
}

//comparing the total change given to the remaining total in the register
if (toPassTotal < totalInRegister) {
output.status = 'OPEN'
} else if (toPassTotal == totalInRegister) {
output.status = 'CLOSED'
}

return output;
}

// Example cash-in-drawer array:
// [["PENNY", 1.01],
// ["NICKEL", 2.05],
// ["DIME", 3.1],
// ["QUARTER", 4.25],
// ["ONE", 90],
// ["FIVE", 55],
// ["TEN", 20],
// ["TWENTY", 60],
// ["ONE HUNDRED", 100]]

checkCashRegister(3.26, 100, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.1], ["QUARTER", 4.25], ["ONE", 90], ["FIVE", 55], ["TEN", 20], ["TWENTY", 60], ["ONE HUNDRED", 100]]);
``````

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