Calculate 6231+2787 by rounding each number to the nearest: 1000 100 50 10

Fredrick designed an experiment in which he spun a spinner 20 times and recorded the results of each spin

The median of a data set is the measure of center that is found by adding the data values and dividing the total by the number of data values that is the value that occurs with the greatest frequency that is the value midway between the maximum and minimum values in the original data set that is the middle value when the original data values are arranged in order of increasing (or decreasing) magnitude

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