Abel walks 2.6 miles each day of the week.
The week has 7 days.
So, to calculate how many miles he walks in one week we simply have to multiply the number of miles that he walks per day (2.6) by the number of days in a week (7).
2.6 miles per day x 7 days = 2.6 x 7 = 18.2 miles a week.