Apple Numbers: Controlling rounding

While I use Excel at work, I tend to use Numbers (part of the Apple Productivity Apps suite) at home. I have sheets that do a number of different things, most of them rife with macros and automatic functions. From time to time, I need to ensure that the result of a function either overstates or understates a result. This cannot be achieved when using the SUM function, so a different function must be used. Luckily, Numbers provides you three functions to achieve just this (as, I would assume, does Excel). They are called ROUND, ROUNDDOWN and ROUNDUP. Their syntax are the same:

ROUND(Number to round;digits)

Where ROUND controls only the decimal places to which the number is rounded, ROUNDDOWN always rounds down, and ROUNDUP always rounds up. The digits argument controls how many decimal places to which the number is rounded. A positive number controls the number of places to include to the right of the decimal point, while a negative number controls the number of zeros to the left of the decimal point. Within the “Number to round” argument, you can perform standard calculation functions, such as addition, subtraction, division, and multiplication.