Round 665749 to the nearest hundred thousand?

Can someone me i’m confused. will give brainliest and a whole bunch of points

(c) the diagram shows the first three shapes of a matchsticks arrangement.first shape = 3second shape = 5third shape = 7given m represents the number of matchstick used to arrange the n'th shape.(i) write a formula to represent the relation between m and n. express m as the subjectof the formula.(ii) 19 matchsticks are used to make the p'th shape. find the value of p.

700 miles the train takes 5 hours to a travel the distance at what unit rate is the train traveling?