math.decimal provides arbitrary-precision fixed-point decimal arithmetic.
It stores values as an integer coefficient plus a decimal scale, so addition,
subtraction, and multiplication stay exact.
Division is exposed through div_prec, which rounds half up to a caller-chosen
number of decimal places. The / operator uses
decimal.default_division_precision.
import math.decimal
price := decimal.from_string('19.99')!
fee := decimal.from_string('1.50')!
total := price + fee
assert total.str() == '21.49'
share := total.div_prec(decimal.from_int(3), 2)!
assert share.str() == '7.16'