@RareBird_15 Ohhh thats an nasty bug that you stumpled onto here, so let me explain.

First lets insert some debug statements to check whats going on: We'll add some console.log statements in the calculateChange function, about after the cash === price if, and print out the following:

• totalCid + price
• totalCid
• change

If you now enter any value (like 2 for example), you'll get this in your console:

Whats that enourmous (broken) looking numbers you might ask. That's an infamous bug when you work with floating point numbers. Floats have an precision; if you make calculations that involve something that goes beyond the precision, weird things happens. For example; just execute this line: 0.1 + 0.2, which every sane human being would say is 0.3 but computers instead produce 0.30000000000000004.

The same thing is happening to you here; since the total sum of your cid would equal to 337.28 in an calculator, computer-math instead results in 337.28000000000003. If you plug in that number instead, you'll see that it indeed responds with the correct output.

An article for further informations on that topic can be found here: https://jvns.ca/blog/2023/02/08/why-does-0-1-plus-0-2-equal-0-30000000000000004/ (Only the first one I've got of from google, there should be plenty others available, just search after "float precision" and "float rounding bugs" etc.)

Also, here's my jsbin with the log statements already applied: https://jsbin.com/kenodulowu/edit?js,console,output