Is the Answer Reasonable?: Grandma Bea's Bake Sale

In Millie’s Kitchen, Grandma Bea is getting ready for the school bake sale, and Millie’s friends help add up the treats. Before anyone writes a total down, Grandma Bea checks it with an estimate: if the answer is far from the estimate, something went wrong!

Remember: Estimate, then check. 214 + 389 is about 200 + 400 = 600, so an answer of 603 makes sense, but 503 or 1,003 does not. A sensible answer is close to the estimate, not exactly the same.

Magic trick: Ask yourself: “Is it about right?” If the answer is a whole hundred or more away from the estimate, check again.