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This content is taken from the Davidson Institute of Science Education at the Weizmann Institute of Science's online course, Maths Puzzles: Cryptarithms, Symbologies and Secret Codes. Join the course to learn more.
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## Davidson Institute of Science Education at the Weizmann Institute of Science

Skip to 0 minutes and 0 seconds Let’s get back to the aliens. Hmmm! The second row. Roman numerals. Well, I’m not sure we know exactly everything. Let’s just recall what we’ve done so far. We’ve done the first line - which was 4 times 142857 is equal to, sorry, is equal to 571428 which is correct. Now we have a house with 7 in it, let’s put it over here, a house with the number 7 in it is equal to CXLII with a bar on the top - what does that bar mean? - DCCCLVII Your turn!

# Try and solve the ancient numeral part of the course challenge

It’s time again for the course challenge. Try and decipher the Roman numeral:
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CXLIIDCCCLVII

You can ask for hints in the discussion, but don’t give away the answer. That you’ll be able to see on the next step. Good Luck!