```go package main func main() { nums := make(chan int, 10) for i := 0; i < 10; i++ { nums <- i } close(nums) for i := 0; i < 3; i++ { go square(nums) } } func square(nums <-chan int) <-chan int { res := make(chan int, 10) for n := range nums { res <- n * n } return res } ```

The provided code has several issues related to the use of channels and goroutines:

1. The sqare function (probably a typo, should be square) takes a channel nums as input and creates a new channel res, into which it writes the squares of the numbers. However, the function returns res, but in main, this returned channel is not used.

2. In main, three goroutines sqare(nums) are started, which read from the same nums channel simultaneously. This may lead to each element being processed by only one goroutine, which might be expected.

3. However, since res is created inside each goroutine and not passed outside, the calculation results are lost.

To fix the code and get the squares of the numbers, you can do the following:

• Create a single output channel res in main.
• Pass it to the goroutines to write results.
• In main, read the results from res.

Example of the corrected code:

package main

import (
    "fmt"
    "sync"
)

func main() {
    nums := make(chan int, 10)
    res := make(chan int, 10)

    for i := 0; i < 10; i++ {
        nums <- i
    }
    close(nums)

    var wg sync.WaitGroup
    for i := 0; i < 3; i++ {
        wg.Add(1)
        go func() {
            defer wg.Done()
            square(nums, res)
        }()
    }

    go func() {
        wg.Wait()
        close(res)
    }()

    for val := range res {
        fmt.Println(val)
    }
}

func square(nums <-chan int, res chan<- int) {
    for n := range nums {
        res <- n * n
    }
}

In this version, three goroutines read from nums in parallel, compute the square, and write to the shared res channel. After all goroutines finish, the res channel is closed, and main prints all results.