decimal value change when fetch NSDictionary in Swift

var dictSelectedPortfolio: NSDictionary!
let abc1 = dictSelectedPortfolio.value(forKey: "abc") // it's double (0.58)

with above line i get correct value but when i multiply this number with 100.0 then it gives error : Cannot convert value of type 'Any?' to expected argument type 'Double'

Now when i try,

let abc1 : Double = dictSelectedPortfolio.value(forKey: "abc") as! Double

here i get 0.579999 which change my calculation. I need 0.58