If you want to round a number to a certain number of decimal places, use the Round function. 

Round (Number, NumDigitsAfterDecimal) 

So, if you call

Round(29.03914, 2)

you will get 29.04 (the last digit is 4 because it has been rounded up).

If you want to round a number to, say the nearest 100, you can either use the Format function, or a more efficient method using the Round function again:

Round(nNumber / 10, 1) * 10

This rounds nNumber to the nearest 10. If you want to round to the nearest 1000, use

Round(nNumber / 1000, 1) * 1000

Simple!