Go言語で数値を文字列に変換する
数値型を文字列に変換（フォーマット）します。
型がわからないときには、fmt.Sprint()を使うと良いかもしれません。
from_num_to_string.go 
package main

import (
	"fmt"
	"strconv"
)

func main() {
	fmt.Println("for int,     use Itoa: " + strconv.Itoa(100))
	fmt.Println("for bool,    use FormatBool: " + strconv.FormatBool(true))
	fmt.Println("for int64,   use FormatInt: " + strconv.FormatInt(100, 10))
	fmt.Println("for float64, use FormatFloat: " + strconv.FormatFloat(100.001, 'e', 2, 64))
	fmt.Println("for FormatInt, we can specify base: " + strconv.FormatInt(100, 2))
	fmt.Println("FormatUint also available: " + strconv.FormatUint(100, 10))

	fmt.Println("")
	fmt.Println("If you don't know type of number, you can use fmt.Sprint()")
	fmt.Println("Sprint with Integer: " + fmt.Sprint(100))
	fmt.Println("Sprint with float:   " + fmt.Sprint(100.1))
}
実行結果 
$ go run from_num_to_string.go
for int,     use Itoa: 100
for bool,    use FormatBool: true
for int64,   use FormatInt: 100
for float64, use FormatFloat: 1.00e+02
for FormatInt, we can specify base: 1100100
FormatUint also available: 100

If you don't know type of number, you can use fmt.Sprint()
Sprint with Integer: 100
Sprint with float:   100.1