Use equivalent representations of numbers such as fractions, decimals, and percents to facilitate estimation. Students use fractions, decimals, or mixed numbers interchangeably when one form of a number makes estimation easier than another form. In their beginning work with percent, students master the common fraction equivalents for familiar percentages and use fractions for estimation in appropriate situations. Determine whether a given estimate is an overestimate or an underestimate. Students decide, as they discuss each new estimation strategy they learn, whether the strategy is likely to give an overestimate, an underestimate, or neither.
Students frequently use guess, check, and revise as a problem solving strategy.
With this strategy, the answer to a problem is estimated, then calculations are made using the estimate to see whether this estimate meets the conditions of the problem, and the estimate is then revised upwards or downwards as a result. For example, students are asked to find two consecutive pages in a book the product of whose page numbers is 1260. An initial guess might be 30 and 31, the check might involve concluding that this product is a little over 900, and, as a result, they might revise their estimate upwards. References Parker, Tom. In One Day.