30 points! The human body is made up of about 37.2 trillion blood cells. That’s a lot of blood cells! Instead of writing 37,200,000,000,000 to express this very large number, we use scientific notation to write it as 3.72 × 1013.

A. Research to find another large or small number from a real-world situation. Write the number in scientific notation. Provide a hint that describes what your number represents.
B. Read another student’s post and guess what that student's number describes. Then write the number in standard form. Try to choose a post that doesn’t have any responses to it yet.
C. Respond to all replies to your post. For each post, check whether the number is correctly written in standard form and whether the student correctly guessed what your number represents. At the close of the discussion, reveal the answer.