How well can you keep numbers in your head?

  1. When you add the square root of 9 to 12 squared, what do you get?
  2. How much is 3 dozen plus 14?
  3. When you add the first 5 even numbers, starting from 2, what do you get
  4. When you add the number of legs on a dog to the number of legs on a centipede, what do you get?
  5. How much is 12 dozen plus half a dozen?

Answers

  1. 147
  2. 50
  3. 30
  4. 104
  5. 150