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?

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Answers

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