Once upon a time, there was an ocean inhabited by tiny numbers, instead of fish! When seven year-old Dora found out about this ocean and its food chain, she was determined to figure out the laws of its ecosystem — which numbers were allowed to consume which others? How did the numbers determine their families and friends (like schools of fish)? Let's embark with Dora on an adventure to unravel this strange ocean’s mysteries.

Note - Circle Prerequisites:
(1) Comfort with addition and subtraction
(2) No more than a passing familiarity with fractions