For this problem, an exact computation is certain to be wrong and will also be a number that is very hard to remember or use in further planning. Determine the reasonableness of an answer by estimating the result of operations. Students estimate the size of a crowd at a rock concert from a picture. They share all of their various strategies with the rest of the class. Students demonstrate their understanding by estimating whether or not they can buy a set of items with a given amount of money.
Students place decimal points in multi-digit numbers to make absurd statements more reasonable.
Develop, apply, and explain a variety of different estimation strategies in problem situations involving quantities and measurement. Students develop the concept of a billion by estimating its size relative to one hundred thousand, one million, and so on. Students estimate the area inside a closed curve in square centimeters and then check the estimate with centimeter graph or grid paper. Students make estimates about things that happen in one day at school after reading about some of the data in In One Day, by Tom Parker. They then interview people around the school or conduct a survey to check their estimates.