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Mixed Number Calculator

Add, subtract, multiply and divide mixed numbers — and convert between mixed numbers and improper fractions — with full working.

Quick Answer: How Do You Calculate With Mixed Numbers?

To calculate with mixed numbers, first turn each one into an improper fraction using whole × denominator + numerator. Then add, subtract, multiply or divide as normal fractions, and convert the answer back to a mixed number in simplest form. For example, 1½ + 2⅓ becomes 3/2 + 7/3 = 23/6 = 3⅚. This calculator shows every step.

Mixed Number Calculator
First mixed number
Second mixed number

Whole numbers only. Leave the Whole box blank for a simple fraction like 3/4. Put a minus sign on the Whole box (or the Numerator if there is no whole part) for a negative value.

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Result
Answer
3 5/6
1 1/2 + 2 1/3
What is a mixed number? A mixed number is a whole number written next to a proper fraction, like 2¾. It means "two wholes plus three quarters". An improper fraction such as 11/4 is the same value written as a single fraction — the top number is simply larger than the bottom.

How to Use the Mixed Number Calculator

Choose Calculate to work with two mixed numbers, or Convert to switch a single value between forms.

Press Calculate or the Enter key. Use Copy result for the answer, or Share link to copy a web address that reopens the page with your numbers already filled in.

The Mixed Number Formulas

mixed → improper: whole × denominator + numerator
add / subtract: a/b ± c/d = (ad ± cb) / bd
multiply: a/b × c/d = ac / bd
divide: a/b ÷ c/d = a/b × d/c

What the letters mean. In a fraction a/b, a is the numerator (how many parts you have) and b is the denominator (how many equal parts make one whole). When two fractions have different denominators, multiplying by bd gives them a common denominator so the parts are the same size and can be counted together.

Why converting first works. A mixed number is really an addition in disguise: 2¾ means 2 + ¾. Turning it into 11/4 gives a single fraction, so the ordinary fraction rules apply with no separate whole number to keep track of. That is why this method never goes wrong, even when subtraction crosses below zero.

When to use each form. Improper fractions are easier to calculate with; mixed numbers are easier to picture and to read. Most teachers expect working shown in improper fractions and the final answer given as a mixed number in simplest form — which is exactly what this calculator produces.

Formula Cheat Sheet

Quick reference

Mixed → improper: (whole × den) + num   e.g. 2¾ = (2×4)+3 = 11/4
Improper → mixed: num ÷ den, remainder over den   e.g. 11/4 = 2 r3 = 2¾
Add / subtract: common denominator first
Multiply: tops × tops, bottoms × bottoms
Divide: flip the second fraction, then multiply
Simplify: divide top and bottom by the GCF

Worked Examples

1. Simple — 1½ + 2⅓

Convert: 1½ = 3/2 and 2⅓ = 7/3
Common denominator 6: 9/6 + 14/6 = 23/6
23/6 = 3⅚

2. Simple — 3¼ − 1½

Convert: 13/4 − 3/2
Common denominator 4: 13/4 − 6/4 = 7/4
7/4 = 1¾

3. Intermediate — 1½ × 2⅓

Convert: 3/2 × 7/3
Multiply across: 21/6, then simplify by 3 → 7/2
7/2 = 3½

4. Intermediate — 1½ ÷ 2⅓

Convert: 3/2 ÷ 7/3
Flip and multiply: 3/2 × 3/7 = 9/14
9/14 (already in simplest form)

5. Advanced — negative result: 1½ − 2⅓

9/6 − 14/6 = −5/6
−5/6. The answer is below zero, so there is no whole part.

6. Advanced — negative input: −1½ + ½

The minus applies to the whole mixed number: −1½ = −3/2
−3/2 + 1/2 = −2/2
−1

7. Real life — a recipe

A recipe needs 2¾ cups of flour. You are making 1½ batches.
11/4 × 3/2 = 33/8
33/8 = 4⅛ cups

8. Real life — a timber cut

A board is 8½ feet long. You cut off 2¾ feet.
17/2 − 11/4 = 34/4 − 11/4 = 23/4
23/4 = 5¾ feet left

Mixed Numbers and Improper Fractions

Mixed numberImproper fractionDecimal
1 1/23/21.5
1 1/45/41.25
1 3/47/41.75
2 1/25/22.5
2 1/37/32.333…
2 3/411/42.75
3 1/310/33.333…
3 5/623/63.8333…
4 1/833/84.125
5 3/423/45.75

Which Form Should You Use?

FeatureMixed numberImproper fraction
Looks like2 3/411/4
Easy to pictureYes — you can see it is almost 3Harder to judge at a glance
Easy to calculate withNo — the whole part gets in the wayYes — ordinary fraction rules apply
Used inRecipes, measurements, everyday speechAlgebra, working out, exam method
Best forReading the final answerDoing the middle steps

Common Mistakes

Watch out for these:
  • Adding the whole numbers and fractions separately, then forgetting to carry. 1¾ + 1½ is not 2 and 1¼ — the fraction part goes over one whole, so the answer is 3¼.
  • Adding denominators. 1/2 + 1/3 is not 2/5. You need a common denominator first.
  • Multiplying without converting. 1½ × 2 is not 2½ — convert to 3/2 × 2 = 3.
  • Forgetting to flip when dividing. Division means multiplying by the reciprocal.
  • Applying a minus sign to only the whole part. −1½ means −3/2, not −1 + ½.
  • Leaving the answer unsimplified, such as writing 21/6 instead of 3½.
  • Leaving an improper fraction as the final answer when the question asks for a mixed number.

Why the Method Works

Every fraction is a division, and every mixed number is an addition. Writing 2¾ as 11/4 does not change the value — it just rewrites 2 + ¾ with a single denominator, because 2 is the same as 8/4. Once both numbers are single fractions, the standard rules apply: a common denominator makes the parts the same size so they can be counted, multiplying scales one fraction by another, and dividing by a fraction is the same as multiplying by its reciprocal. Simplifying at the end divides the top and bottom by the same number, which never changes the value either.

Did you know? Mixed numbers are unusual in mathematics because writing two things side by side normally means multiply — as in 2x. With mixed numbers it means add. That inherited quirk from everyday measurement is exactly why algebra prefers improper fractions and avoids mixed numbers almost entirely.
Pro tip. Simplify before you multiply. For 4/9 × 3/8, cancel the 3 into the 9 and the 4 into the 8 first, giving 1/3 × 1/2 = 1/6. Much easier than multiplying to 12/72 and reducing afterwards.
Pro tip. Estimate first so you can spot a wrong answer. 3⅞ + 2⅛ is roughly 4 + 2 = 6, so an answer of 6 is believable — but an answer of 5⅛ tells you something went wrong.

Practice Questions

Beginner (with answers)

  1. Convert 3¼ to an improper fraction.
  2. Convert 9/2 to a mixed number.
  3. Work out 1½ + 1½.
  4. Work out 2¾ − 1¼.
  5. Work out 1½ × 2.
Show answers

1) 13/4   2) 4½   3) 3   4) 1½   5) 3

Advanced (with answers)

  1. Work out 2⅗ + 1¾.
  2. Work out 3⅓ − 4½.
  3. Work out 2¼ × 1⅓.
  4. Work out 4½ ÷ 1½.
  5. Work out −2¼ + ¾.
Show answers

1) 4 7/20   2) −1 1/6   3) 3   4) 3   5) −1½

Real-Life Applications

Cooking. Recipes are written in mixed numbers — 1½ cups, 2¾ teaspoons — so scaling a batch up or down means multiplying mixed numbers.

Construction and woodworking. Imperial measurements use mixed numbers constantly: a board 8½ feet long, a bolt 1⅝ inches. Cutting lists are mixed-number subtraction.

Education. Mixed numbers appear from upper primary through to secondary school, and converting between forms is a standard exam skill.

Engineering and trades. Drill sizes, pipe diameters and material thicknesses are often fractional, and totals must be added precisely rather than rounded.

Sport and time. Race distances and training splits are frequently expressed as mixed numbers, such as running 3½ laps or resting 1¼ minutes.

🔑 Key Takeaways

  • Convert to improper fractions first: whole × denominator + numerator
  • Add and subtract need a common denominator; multiply and divide do not
  • Dividing means multiplying by the reciprocal — flip the second fraction
  • Give the final answer as a mixed number in simplest form
  • A minus sign applies to the entire mixed number, not just the whole part

Frequently Asked Questions

What is a mixed number?

A mixed number is a whole number written together with a proper fraction, such as 2 3/4. It means the whole number plus the fraction, so 2 3/4 is 2 + 3/4.

How do you add mixed numbers?

Convert each mixed number to an improper fraction, give them a common denominator, add the numerators, then convert the answer back to a mixed number in simplest form. So 1 1/2 + 2 1/3 = 3/2 + 7/3 = 23/6 = 3 5/6.

How do you subtract mixed numbers?

Convert both to improper fractions, use a common denominator, then subtract the numerators. Working this way handles answers that fall below zero without any extra borrowing steps.

How do you multiply mixed numbers?

Convert both to improper fractions, multiply the numerators together and the denominators together, then simplify. So 1 1/2 x 2 1/3 = 3/2 x 7/3 = 21/6 = 3 1/2.

How do you divide mixed numbers?

Convert both to improper fractions, flip the second fraction, then multiply. So 1 1/2 divided by 2 1/3 = 3/2 x 3/7 = 9/14.

How do you convert a mixed number to an improper fraction?

Multiply the whole number by the denominator and add the numerator, keeping the same denominator. For 2 3/4 that is 2 x 4 + 3 = 11, giving 11/4.

How do you convert an improper fraction to a mixed number?

Divide the numerator by the denominator. The whole-number part of the answer becomes the whole number and the remainder becomes the new numerator. So 11/4 is 11 divided by 4 = 2 remainder 3, giving 2 3/4.

What is the difference between a mixed number and an improper fraction?

They are two ways of writing the same value. A mixed number such as 2 3/4 is easier to picture, while the improper fraction 11/4 is easier to calculate with.

Can a mixed number be negative?

Yes. The minus sign applies to the whole mixed number, so -1 1/2 means -(1 + 1/2), which is -3/2. It does not mean -1 plus 1/2.

How do you write a mixed number in simplest form?

Simplify the fraction part by dividing the numerator and denominator by their greatest common factor, and carry any extra whole from an improper fraction part into the whole number. So 2 4/8 becomes 2 1/2.

How do you convert a mixed number to a decimal?

Divide the numerator by the denominator and add the whole number. For 2 3/4, 3 divided by 4 = 0.75, so the decimal is 2.75. This calculator shows the decimal alongside every answer.

How do you convert a decimal to a mixed number?

Keep the whole part, write the decimal part over its place value, then simplify. So 2.75 becomes 2 and 75/100, which reduces to 2 3/4.

Why convert to improper fractions before calculating?

A mixed number is really a whole number plus a fraction, which makes two parts to track. Converting to a single improper fraction means the ordinary fraction rules work every time, including when a subtraction crosses below zero.

Does this calculator show the working?

Yes. Every answer lists the conversion to improper fractions, the common denominator or reciprocal step, the arithmetic, and the final simplification, so it can be used for learning as well as checking.

Can you add a whole number and a mixed number?

Yes. Treat the whole number as a fraction over 1 by entering it with numerator 0 and denominator 1. For example, 3 + 2 1/4 becomes 3/1 + 9/4 = 21/4 = 5 1/4. You can also simply add the whole numbers and keep the fraction part unchanged.

Is this Mixed Number Calculator free?

Yes. It is free with no sign-up, works on any device, and runs in your browser so your entries stay private.

References

Last updated: July 2026
Reviewed by the MegaCalcOnline Editorial Team using standard fraction arithmetic and trusted educational references. All calculations use exact integer arithmetic, so answers are never affected by decimal rounding, and every result is reduced by the greatest common factor. This page is for educational purposes.