Fake bills may have serial figures that aren't evenly spaced or that are not completely aligned in a row. In case you gained several suspicious bills, see If your serial numbers are the same on both of those bills. If they are exactly the same, then they are copyright notes. https://fakeusdollarbillforsaleon47924.thenerdsblog.com/44561441/fake-us-dollar-bill-for-sale-things-to-know-before-you-buy