Memory Game Numerical PrefixesOnline version Practice identifying number-based prefixes. by Marc Hughes 3 Some that happens biannually takes place... Eight legged sea creature A three wheeled bike centi- Tricycle 4 8 100 tri- Quadruplets One hundred pennies Ten years is a... Octopus deca- every two years. A dollar has... quad- 10 Four identical siblings would be... octo- decade