Use rounding to check answers to calculations 2 - Reasoning

In a mathematical exercise focused on developing reasoning skills, students are tasked with using rounding as a method to check their answers to calculations involving addition and subtraction. The challenge is to find pairs of numbers that, when rounded to the nearest 1,000, will result in an estimated total of 11,000. This exercise prompts students to think critically about the relationship between actual numbers and their rounded estimates, enhancing their understanding of approximation and its practical applications in verifying the accuracy of their work.

To illustrate, two examples are provided: 31,958 minus 20,500, and 3,249 plus 7,872. In both instances, the numbers involved in the calculations can be rounded to the nearest thousand—32,000 and 20,000 for the first example, and 3,000 and 8,000 for the second—to produce an estimated sum or difference of 11,000. Students are encouraged to explore other numerical combinations that fit the criteria of rounding to the nearest thousand and yielding the same estimated result. This activity not only reinforces their addition and subtraction skills but also introduces them to the concept of estimation as a useful tool for checking the plausibility of their answers.