Can someone help me with this question ?

Blank × 10-3 is 2,000 times greater than 1.9 × 10-6. it is also blank times greater than 9.5 × 10-4.

1. the wheeling bridge in west virginia is about 307 meters long. if you walk with a stride of about meter, about how many steps would it take you to cross this suspension bridge?

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?