Here’s a short practice exercise about Ruby:

### Problem:

Write a Ruby program that takes a list of numbers as input and returns the sum of all even numbers in the list.

### Example:

`rubyCopy code````
numbers = [2, 3, 6, 8, 9, 10, 11]
puts sum_even_numbers(numbers) #=> 26
```

### Solution:

`rubyCopy code````
def sum_even_numbers(numbers)
sum = 0
numbers.each do |num|
if num.even?
sum += num
end
end
return sum
end
numbers = [2, 3, 6, 8, 9, 10, 11]
puts sum_even_numbers(numbers) #=> 26
```

In this program, we define a method called `sum_even_numbers`

that takes a list of numbers as input. We then initialize a variable called `sum`

to 0, which we will use to keep track of the sum of all even numbers in the list.

We then iterate over each number in the list using the `each`

method, and check whether the number is even using the `even?`

method. If the number is even, we add it to the `sum`

variable.

Finally, we return the `sum`

variable, which contains the sum of all even numbers in the list. We test our method by passing in a list of numbers and printing the result to the console.

Note: This is just one possible solution to the problem, and there are many other ways to write a Ruby program that solves this task.