Invalid value for Integer
<p>This code:</p>

<pre><code>my_name = 'Alessandro Tegagni'
my_age = '31'
my_height = '170 '#cm
my_weight = '82 '#kg
my_eyes = 'Brown'
my_teeth = 'White'
my_hair = 'Brown'

puts "let is talk about %s." % my_name
puts "he is %d cm tall." % my_height
puts "he is %d kg heavy." % my_weight
puts "actually that is not too heavy."
puts "he is got %s eyes and %s hair." % [my_eyes,my_hair]
puts "his teeth are usually %s depending on the coffee or tea" % my_teeth

puts "if I add %d, %d, and %d I get %d." % [my_age,my_height,my_weight,my_age+my_height+my_weight]
</code></pre>

<p>raises an error:</p>

<pre><code>:17:in `%': invalid value for Integer(): "31170 82 " (ArgumentError)
</code></pre>

<p>What is the error?</p>