Add, subtract, multiply and divide fractions and mixed numbers — every result is simplified and also shown as a decimal.
Mixed numbers are converted to improper fractions first (whole × denominator + numerator), the operation is carried out, and the result is reduced by dividing numerator and denominator by their greatest common divisor. Addition and subtraction use a common denominator; multiplication multiplies straight across; division multiplies by the reciprocal of the second fraction. The simplified mixed-number form is shown first because it is the form most recipes, measurements and school answers use.
How is a fraction simplified? Numerator and denominator are divided by their greatest common divisor — the largest number that divides both — until no common factor remains.
How are mixed numbers handled? A mixed number such as 1 1/2 is treated as 3/2 during the calculation, and the answer is converted back to mixed form when it is larger than one.
Why show a decimal as well? Decimals make comparison and measurement conversion easier, while the fraction keeps the exact value. A repeating decimal is rounded to six places, so the fraction is the exact result.