Deciding if an Answer is Reasonable Worksheet Download
This worksheet gives a three-part word problem - a total and two of the three parts - along with an answer someone has proposed for the missing part, and asks yes or no: is it reasonable? Every wrong answer on the sheet is the result of a real mistake rather than a random number: the two known parts added together instead of subtracted, one part taken off the total with the other forgotten, or a part added to the total instead of removed. Wrong answers are always either larger than the total, which a single part can never be, or at least double the true value, so the verdict never rests on a close call. Where the other sheets on this standard ask students to compute an answer, this one asks them to judge a result someone else produced, which is the second half of what the standard asks for.
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About this worksheet
Students read a word problem with an answer someone has proposed and decide yes or no whether that answer is reasonable.
Student objectives
- Judge whether an answer someone else gave is reasonable
- Use estimation to check an answer without working it out exactly
- Recognize that one part can never be larger than the whole
- Decide when an answer is too far off to be believable
Everyday practice
- Check whether the change you were handed back looks about right
- Decide if a total on a receipt seems believable before paying
- Judge whether a friend's answer to a homework problem makes sense
- Estimate whether you have enough money left after two purchases