--------Math week!--------

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Across
  1. 5. week is celebrated on whose birthday?
Down
  1. 1. He was the first person to calculate the value of pi
  2. 2. This person is known as the "human computer"
  3. 3. A Greek philosopher who had given an important theorem in geometry
  4. 4. Another Greek philosopher known for giving many postulates and theorems of geometry