What are some situations in which estimating a sum or difference is useful? Why is it useful in these situations?
what exactly are these situations can you tell me and maybe I could help you out.
Suppose I am in a store buying a shirt, a tie, and slacks. Each of the prices ends in 99 cents, and it is hard to add the exact amounts in my head. I can make an estimate, and decide if this is too much to spend or not.