diff --git a/eBook/09.4.md b/eBook/09.4.md
index afe724c..c543e53 100644
--- a/eBook/09.4.md
+++ b/eBook/09.4.md
@@ -9,7 +9,7 @@
 示例 9.2 [big.go](examples/chapter_9/big.go)：
 
 ```go
-package main

import (
	"fmt"
	"math""
	"math/big"
)

func main() {
	// Here are some calculations with bigInts:
    im := big.NewInt(math.MaxInt64)
    in := im
    io := big.NewInt(1956)
    ip := big.NewInt(1)
    ip.Mul(im, in).Add(ip, im).Div(ip, io)
    fmt.Printf("Big Int: %v\n", ip)
    // Here are some calculations with bigInts:
    rm := big.NewRat(math.MaxInt64, 1956)
    rn := big.NewRat(-1956, math.MaxInt64)
    ro := big.NewRat(19, 56)
    rp := big.NewRat(1111, 2222)
    rq := big.NewRat(1, 1)
    rq.Mul(rm, rn).Add(rq, ro).Mul(rq, rp)
    fmt.Printf("Big Rat: %v\n", rq)
 }
+package main

import (
	"fmt"
	"math"
	"math/big"
)

func main() {
	// Here are some calculations with bigInts:
    im := big.NewInt(math.MaxInt64)
    in := im
    io := big.NewInt(1956)
    ip := big.NewInt(1)
    ip.Mul(im, in).Add(ip, im).Div(ip, io)
    fmt.Printf("Big Int: %v\n", ip)
    // Here are some calculations with bigInts:
    rm := big.NewRat(math.MaxInt64, 1956)
    rn := big.NewRat(-1956, math.MaxInt64)
    ro := big.NewRat(19, 56)
    rp := big.NewRat(1111, 2222)
    rq := big.NewRat(1, 1)
    rq.Mul(rm, rn).Add(rq, ro).Mul(rq, rp)
    fmt.Printf("Big Rat: %v\n", rq)
 }
 ```
 
输出结果：