You need to round off the two figures ($2.49 rounds to $2.50 and $1.04 rounds to $1.00). This makes is easy to estimate the answer. Two at $2.50 is $5.00 and 2 at $1.00 is $2.00. So, the total is about $7.00. When problems ask to estimate, they are not looking for an exact answer. They want you to figure out how to do it easily in your head.