By looking at the number line, you can see how far 100 and 1000 are away from each other. ... We can double check by counting 7 intervals from 50 on the number line. The arrow reaches the number 85.

First put 44 on the number line, ... 40 and 50 are the closest multiples of ten to 44. 44 is 4 away from 40 and 6 away from 50. 44 is closer to 40 and so it is rounded down to 40.