Melinda rents paddle boats down at the pier. she uses 5.5 feet of nylon rope to tie off each boat. she started with 80 feet of rope. after securing all the boats, she was left with more than 3 feet of rope. how many boats did melinda tie off?

Long division setup showing an incomplete calculation. 12 is in the divisor, 6839 is in the dividend, and 5 hundreds and 6 tens is written in the quotient. 6000 is subtracted from 6839 to give 839. an unknown value represented by a box is being subtracted from 839. what number should be placed in the box to complete the division calculation?