Deciding if a Fraction Answer is Reasonable Worksheet Download
Free 5th Grade (5nf2) math worksheets on Deciding if a Fraction Answer is Reasonable. Each worksheet has 18 problems with an answer key and are ideal for teachers and homeschooling. You can download the PDF, create a set of flash cards or set it up for online learning.
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About this worksheet
Each worksheet has 18 fraction sums with an answer filled in, to be judged reasonable or not using estimation.
This worksheet gives a fraction sum with an answer already filled in and asks whether it is reasonable. The wrong answers come from adding the numerators and the denominators - the single most common mistake in fraction addition, and exactly what a benchmark estimate catches, since three eighths is about a half and five sixths is about one so the answer must be near one and a half. Wrong answers that land close to the true value are discarded, because reasonableness has no honest answer when the gap is a twentieth. Sheets can be customized, turned into flash cards, or assigned for online learning.
Student objectives
- Judge whether a fraction sum is reasonable.
- Use benchmarks to estimate before checking.
- Recognize the error of adding numerators and denominators.
Everyday practice
- Estimate a fraction sum before working it out.
- Ask whether an answer can be smaller than one of the parts.
- Explain why adding across the top and bottom is wrong.