Fiona starts at the beginning of a hiking trail and walks 4/5 mile. She counts the mileage markers that are placed every 1/10 mile along the trail. How many markers does she count?

First you have to make 4/5 have the same denominator as 1/10. Which is ten.

So then you get 8/10. By multiplying the numerator and denominator by 2. Since you see one marker every 1/10 of a mile, she would see 8 markers.