# Estimating Sums and Differences of Fractions Calculator

> Estimate a fraction sum or difference using benchmark fractions, and compare it with the exact result.

Page: https://askcalculators.com/calculator/estimating-sums-and-differences-of-fractions-calculator/
Definition: https://askcalculators.com/calculator/estimating-sums-and-differences-of-fractions-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/estimating-sums-and-differences-of-fractions-calculator/schema.json
Version: 1.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/estimating-sums-and-differences-of-fractions-calculator/?operation=add&numeratorA=5&denominatorA=8&numeratorB=7&denominatorB=12&benchmark=half

## Inputs
- operation: Operation; type=select; required; default=add; values=add|subtract
- numeratorA: First numerator; type=number; required; default=5
- denominatorA: First denominator; type=number; required; default=8
- numeratorB: Second numerator; type=number; required; default=7
- denominatorB: Second denominator; type=number; required; default=12
- benchmark: Benchmark increment; type=select; required; default=half; values=whole|half|quarter|tenth

## Outputs
- estimate: Estimated result; format=number; primary
- exactFraction: Exact reduced result; format=text
- exactDecimal: Exact decimal; format=number
- estimatedTerms: Rounded terms; format=text
- absoluteError: Absolute error; format=number

## Formula
round each fraction to a benchmark increment, then add or subtract; exact result uses a common denominator

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.