Who discoverd zero?

Pam has a 4-pound bag of dry cat foodEvery day she puts out 4 ounces of dry cat food? How do you write 1560 billion in scientific notation? What can go into 5 evenly? How do you get 1.15 with quarters and dimes? What is 14 percent as a whole number? What is 26 written as a fraction? What 800 times 9? What is the value of a 1996 five dollar gold piece? What are percentiles? What is quarter cast? What term best completes the diagram? What is 230 divided by 30? 1 1 2 3 5 8 13 21 10946? What can you do in a hour? Is wow a adverb? How much water does a hose carry that is one and 34 inches in diameter times 100 feet? How do you pronounce Sieve of Eratosthenes? What is 20 percent of 4500000? What symbol can you use on a spreadsheet to automatically add a set of numbers together? What is 100 x 42?