Each roll contains 80cm which is the same as 0.8 meters. Because he needs 5.6 meters, divide 5.6 by 0.8 and you 7. The seven is the number of rolls of tape he will need to purchase. Each roll costs $5 so multiply 7 by 5 and you will see that Carson will need to spend $35 if he wants to get that much tape. Hope that helps!