Free · Fractions and rounding

Fraction and Mixed-Sum Decimal Rounding

Convert signed fractions or additive mixed sums to rounded decimals with preset or custom precision.

Formula & worked example
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Calculator inputs

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How to use this calculator

Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

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Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

3/8 = 0.375.

decimal = W + numerator/denominator, rounded to the selected places

Worked example

Enter these known values and leave the other values blank.

Numerator (n): 3
Denominator (d): 8

Decimal conversion: 0.375

Assumptions and limitations

The captured mixed form adds W + numerator/denominator. A negative W does not change the sign of a separately positive numerator.
Exact half ties round toward positive infinity. Choose a preset or any integer custom precision from zero through sixteen. The denominator is nonzero; the scaled rounding argument magnitude is below 10^50.

Common questions

How do I enter a negative mixed amount?

The model adds the whole part and fraction. Enter a negative numerator as well when the full quantity should be negative.

How are ties rounded?

At an exact halfway point, rounding selects the larger value, including for negative inputs.

References

Translate captured decimal-place rounding into exact local floor arithmetic, retaining the captured half-toward-positive-infinity convention, additive mixed-number meaning, all preset/custom decimal counts and forward-only output. Bound the scaled rounding argument below 10^50 for exact integer precision.

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