Can You Find The Landmark For This Set Of Numbers: 929, 842, 986, 978, 869, 732, 898,986, 900, 899, 986, 920, 842?

Your problem is very simple. The first step would be to arrange the numbers in ascending or descending order.
The following are counts for minimum, maximum, range and median.
732, 842, 842, 869, 898, 899, 900, 920, 929, 978, 986 , 986, 986

Minimum value = 732
Maximum value = 986
Range = Highest value -Lowest value = 986-732
Range = 254
Mode = The most frequent value = 986
Median = The middle value = 900