I just don’t see how this isn’t the process. If you understand what the dollars and cents mean then it’s still just adding 1. I was also a cashier for years and never ever saw this be an issue. I met or trained dozens if not hundreds of cashiers and this was never such a problem that couldn’t be learned. If you can be trusted to handle cash you should be able to handle adding small values to a number

You seriously couldn’t be bothered to add 1 in your head? Honestly, that is terrifying. It also makes it so you have less work overall. Handing a $10 is much easier than handing a $5 and 4 $1s.