The nile river, the longest river in the world, is 66.7x100 kilometers long. What is the nile's length?

Well if you multiply 66.7 x 100 you get 6,670.0. When multiplying by numbers like 10, 100, 1,000, etc, just simply transfer the 0's. So in this case, there are 2 0's in 100, so you add 2 of the 0's behind 66.7. So when you add the 2 of the 0's you get 6,670.0 which should be your answer.