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package main
import (
"fmt"
"math"
"strconv"
"strings"
)
func main() {
value := "12.456"
digit := 3
defautDigit := 1
parseFloat, _ := strconv.ParseFloat(value, 64)
repeatDigit := strings.Repeat("0", int(math.Abs(float64(defautDigit)-float64(digit)))+1)
totalDigit, _ := strconv.Atoi(fmt.Sprintf("1%s", repeatDigit))
fmt.Println(math.Round(parseFloat*float64(totalDigit)) / float64(totalDigit))
}