Swift 3 has a “decimal” number type that can represent values such as 0.3 that are inexactly represented in Double or Float types. According to this article: An instance can represent any number that can be expressed as mantissa x 10^exponent where mantissa is a decimal integer up to 38 digits long, and exponent is an integer from –128 through 127. Note this is not the same as Python’s arbitrary-precision integer arithmetic.