Block that outputs the input after rounding it to n digits.
For example,
n = 0 to round to the nearest integer,
n = 1 to round to the next decimal point, and
n = -1 to round to the next multiple of ten.
Hence, the block outputs
y = floor(u*(10^n) + 0.5)/(10^n) for u > 0,
y = ceil(u*(10^n) - 0.5)/(10^n) for u < 0.