Reason Abstractly and Quantitatively
Estimates help us predict the reasonableness of an answer. Having students make an estimate before they perform the calculation, and even writing the estimate next to the problem, can help them to focus on making the numbers (and the problem) make sense. Example: 3.2 x 9.8 = Students use benchmarks to determine that 3.2 is close to 3 and 9.8 is close to 10, therefore, a reasonable estimate would be 3 x 10 = 30. If students perform the actual…