5th grade
posted by cindy .
lonny has $15 to buysome groceries for his mom .milkcosts $2.39,bread costs $1.29,eggs costs $0.79, and mayonnaise costs $2.49. if he bys one of each item ,can he expect to get $10 in change?

No.
Add the 4 prices and subtract from $15.
You can estimate by rounding to the nearest dollar and then adding. 
add the costs, and subtract from 15.
Estimating 2.5+1+1+1.5=6
156 is not a ten dollar bill in change. 
Of course, a few years ago I bought gasoline walked into the store to pay, got also a cup of coffee, offered the clerk $50.00 bill, he told me my change was $512.00, and he couldn't give it to me as he did not have that much in the register. I told him he did it wrong, he pointed to the electronic display, and told me to look! $512.00. I noticed the next week he was gone.
Estimating is a very valuable tool, it allows you to check the register.