Enter two mixed numbers and choose an operation to calculate.
Mixed Number Arithmetic Operations
To add, subtract, multiply or divide mixed numbers, turn each one into an improper fraction first (2 1/2 = 5/2), do the operation, then convert the answer back. For example, 1 1/2 + 2 1/3 = 3/2 + 7/3 = 23/6 = 3 5/6. The calculator above does this for all four operations and shows every step, plus the improper fraction, decimal and percent.
A mixed number combines a whole number and a proper fraction, such as 2 and 1/2 or 3 and 3/4. To perform arithmetic on mixed numbers, the standard approach is to convert them to improper fractions first, perform the operation, then convert the result back to a mixed number.
Converting to improper fraction: multiply the whole number by the denominator, add the numerator, keep the same denominator. Example: 2 and 1/2 = (2×2+1)/2 = 5/2.
Adding Mixed Numbers
Subtracting Mixed Numbers
Multiplying Mixed Numbers
Dividing Mixed Numbers
More Worked Examples
Subtraction with borrowing: 5 1/4 − 2 2/3
Improper fractions: 21/4 − 8/3. Over the common denominator 12 that is 63/12 − 32/12 = 31/12 = 2 7/12. Done by hand in mixed form, 1/4 (3/12) is smaller than 2/3 (8/12), so you borrow 1 from the 5: 5 3/12 becomes 4 15/12, and 4 15/12 − 2 8/12 = 2 7/12. Same answer.
Multiplication: 3 1/3 × 2 1/4
10/3 × 9/4 = 90/12. The greatest common factor is 6, so 90/12 = 15/2 = 7 1/2.
Division: 4 1/2 ÷ 1 1/8
9/2 ÷ 9/8 = 9/2 × 8/9 = 72/18 = 4. A whole-number answer means 1 1/8 fits into 4 1/2 exactly four times.
Scaling a recipe: 1 3/4 cups × 1 1/2
Making one and a half batches of a recipe that needs 1 3/4 cups of flour: 7/4 × 3/2 = 21/8 = 2 5/8 cups.
A negative mixed number: −1 1/2 + 3/4
−1 1/2 means −(1 + 1/2) = −3/2, not −1 + 1/2. So −3/2 + 3/4 = −6/4 + 3/4 = −3/4. In the calculator, type −1 in the whole box and 1/2 in the fraction boxes.
Mixed Numbers as Improper Fractions and Decimals
Digits in brackets repeat, so 1.(3) means 1.333...
| Mixed number | Improper fraction | Decimal |
|---|---|---|
| 1 1/4 | 5/4 | 1.25 |
| 1 1/3 | 4/3 | 1.(3) |
| 1 1/2 | 3/2 | 1.5 |
| 1 2/3 | 5/3 | 1.(6) |
| 1 3/4 | 7/4 | 1.75 |
| 2 1/4 | 9/4 | 2.25 |
| 2 1/2 | 5/2 | 2.5 |
| 2 2/3 | 8/3 | 2.(6) |
| 2 3/4 | 11/4 | 2.75 |
| 3 1/8 | 25/8 | 3.125 |
| 3 3/8 | 27/8 | 3.375 |
| 4 5/6 | 29/6 | 4.8(3) |
| 5 7/16 | 87/16 | 5.4375 |
The rule behind every row: a b/c = (a × c + b)/c. For 5 7/16 that is (5 × 16 + 7)/16 = 87/16.
Mistakes to Avoid
- Multiplying the parts separately. 2 1/2 × 2 1/2 is not 4 1/4 (2 × 2 plus 1/2 × 1/2). Convert first: 5/2 × 5/2 = 25/4 = 6 1/4.
- Subtracting the fractions backwards. In 5 1/4 − 2 2/3 you cannot take 1/4 from 2/3 and hope it works out. Borrow 1 from the whole part, or use improper fractions.
- Leaving the fraction part unsimplified. 2 4/8 should be written 2 1/2.
- Leaving an improper fraction inside a mixed number. 3 5/4 is really 4 1/4, because 5/4 = 1 1/4.
- Splitting the sign. −2 1/3 is −7/3. Treating it as −2 + 1/3 gives −5/3, which is wrong.
For plain fractions without a whole part, the fraction calculator is quicker. To turn a decimal measurement such as 2.375 into a mixed number, use the decimal to fraction calculator.