double amount = 27.65;
int num20, num10, num5, num2, num1, num50c, num20c, num10c = 0;

do {
    if (amount - 20 >= 0) { //check to see that you can subtract the denomination
        //shorthand for subtracts 20 from amount and assigns it to amount, same as using amount = amount - 20;
        amount -= 20;
        num20++; //Increments num20 by 1;
    } else { //If you can't subtract, then leave the loop.
        break; //breaks out of the do-while loop;
    }
} while (1==1); //keeps the loop running (because 1 always equals 1) - hint there's a better way of doing it.

do {
    if (amount - 10 >= 0) { //check to see that you can subtract the denomination
        //shorthand for subtracts 10 from amount and assigns it to amount, same as using amount = amount - 10;
        amount -= 10;
        num10++; //Increments num10 by 1;
    } else { //If you can't subtract, then leave the loop.
        break; //breaks out of the do-while loop;
    }
} while (1==1); //keeps the loop running (because 1 always equals 1) - hint there's a better way of doing it.

System.out.println("$20: " + num20 + etc,etc,etc)