Reasonableness means checking whether an answer makes sense before accepting it. Estimating first gives you the size the answer should be, so a misplaced decimal or a dropped digit shows up immediately.
Math Dictionary / Reasonableness
Reasonableness
Reasonableness is checking whether an answer makes sense for the problem.
Problem SolvingGrade 3Grade 4Grade 5Grade 6Grade 7Grade 8GEDSATACT
What it means
You can use estimation, units, and context to test an answer.
Also called: makes sense
Examples
| A negative length is not reasonable |
| $800 for one pencil is not reasonable |
| Estimate to check a calculation |
Common mistake
An answer can be mathematically calculated but still not make sense in context.
Try one
Question: Why is 3.5 people not a reasonable answer for number of students?
Show answer
Because the number of students must be a whole number.