What this calculator does
Estimate a fraction sum or difference using benchmark fractions, and compare it with the exact result.
How it works
The calculator evaluates round each fraction to a benchmark increment, then add or subtract; exact result uses a common denominator. Inputs are checked before calculation, and invalid values such as zero denominators or out-of-range selections produce a clear error instead of a misleading result.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
6-
?operation=OperationChoice · Required · Default: add · Accepted values: add, subtract
-
?numeratorA=First numeratorNumber · Required · Default: 5
-
?denominatorA=First denominatorNumber · Required · Default: 8
-
?numeratorB=Second numeratorNumber · Required · Default: 7
-
?denominatorB=Second denominatorNumber · Required · Default: 12
-
?benchmark=Benchmark incrementChoice · Required · Default: half · Accepted values: whole, half, quarter, tenth
Outputs
5-
estimateEstimated resultNumber · Primary output
-
exactFractionExact reduced resultText
-
exactDecimalExact decimalNumber
-
estimatedTermsRounded termsText
-
absoluteErrorAbsolute errorNumber
Inputs and results
The inputs are Operation, First numerator, First denominator, Second numerator, Second denominator, Benchmark increment. Results include Estimated result, Exact reduced result, Exact decimal, Rounded terms, Absolute error.