Answer:
8246=x+180
x=8066 miles
Step-by-step explanation:
Let the initial readings be x
The final reading is the sum of initial reading and distance covered hence
Final=Initial + distance covered
Substituting 8246 miles for the final miles and 180 miles for the distance traveled to Grandma's house
8246=x+180
Solving for x
x=8246-180=8066 miles