The ADR (Average Daily Range) is the daily high – daily low / number of days in the count.
The last 5 days range for the S&P 500 Emini March 20 futures contract are 56+28+46.50+37+56.50 totaling 224 diver that number by 5 and you get 44.8 or basically 45. You can take this out for any number of days that wish to count.
How might this be useful as a trader. You could use it to find possible pausing points in a directional market. Today the ES March 20 futures are down about 35 handles. WE are getting to a point near the ADR. Prices a usually like rubber bands. They do no usually hand out away from their midpoints often. On a day like today a counter=trend trader might consider a long order just in front of that -45 number or around 3244 in this case.
A trader might also consider these ranges in calculating their risk. You could use a number that is 1/4 of the ADR as a stop number a a target of 1/2 the ADR for their first scale for a 1:2 risk/reward ratio. These for each trader to decide.