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Mixed Numbers and Improper Fractions — How to Convert

Grade: 6-7 | Topic: Arithmetic

What You Will Learn

A mixed number like 3123\frac{1}{2} combines a whole number and a fraction. An improper fraction like 72\frac{7}{2} has a numerator larger than its denominator. Both represent the same value — you need to move fluently between the two forms depending on the operation you are performing.

Theory

What is a mixed number?

A mixed number has three parts:

2whole34fraction\underbrace{2}_{\text{whole}}\underbrace{\frac{3}{4}}_{\text{fraction}}

It means 2+342 + \frac{3}{4}. The fraction part is always proper (numerator smaller than denominator).

What is an improper fraction?

An improper fraction has a numerator greater than or equal to its denominator:

114,73,55\frac{11}{4}, \quad \frac{7}{3}, \quad \frac{5}{5}

55=1\frac{5}{5} = 1 is technically improper (numerator equals denominator), but is usually just written as 1.

Converting a mixed number to an improper fraction

Rule: Multiply the whole number by the denominator, add the numerator, keep the denominator.

abc=a×c+bca\frac{b}{c} = \frac{a \times c + b}{c}

Example: 325=3×5+25=1753\frac{2}{5} = \frac{3 \times 5 + 2}{5} = \frac{17}{5}

Converting an improper fraction to a mixed number

Rule: Divide numerator by denominator. Quotient = whole number, remainder = new numerator.

175:17÷5=3 remainder 2325\frac{17}{5}: \quad 17 \div 5 = 3 \text{ remainder } 2 \quad \Rightarrow \quad 3\frac{2}{5}

Why improper fractions are easier to compute

When multiplying or dividing fractions, improper fractions simplify the process — you don't need to deal with the whole-number part separately.

Adding with unlike denominators also becomes cleaner once everything is improper:

112+213=32+73=96+146=236=3561\frac{1}{2} + 2\frac{1}{3} = \frac{3}{2} + \frac{7}{3} = \frac{9}{6} + \frac{14}{6} = \frac{23}{6} = 3\frac{5}{6}

Worked Examples

Example 1 — Mixed number to improper fraction

Convert 4374\frac{3}{7} to an improper fraction.

Step 1: Multiply the whole number by the denominator: 4×7=284 \times 7 = 28.

Step 2: Add the numerator: 28+3=3128 + 3 = 31.

Step 3: Keep the denominator: 317\dfrac{31}{7}.

Example 2 — Improper fraction to mixed number

Convert 296\dfrac{29}{6} to a mixed number.

Step 1: Divide: 29÷6=429 \div 6 = 4 remainder 55.

Step 2: The whole number is 44, the new numerator is 55, denominator stays 66.

Answer: 4564\dfrac{5}{6}

Example 3 — Adding mixed numbers

Calculate 234+1122\dfrac{3}{4} + 1\dfrac{1}{2}.

Step 1: Convert to improper fractions: 114\dfrac{11}{4} and 32\dfrac{3}{2}.

Step 2: Find a common denominator (LCD = 4): 114+64=174\dfrac{11}{4} + \dfrac{6}{4} = \dfrac{17}{4}.

Step 3: Convert back: 17÷4=417 \div 4 = 4 remainder 114144\dfrac{1}{4}.

Example 4 — Multiplying mixed numbers

Calculate 123×2141\dfrac{2}{3} \times 2\dfrac{1}{4}.

Step 1: Convert: 53×94\dfrac{5}{3} \times \dfrac{9}{4}.

Step 2: Multiply numerators and denominators: 5×93×4=4512\dfrac{5 \times 9}{3 \times 4} = \dfrac{45}{12}.

Step 3: Simplify: 4512=154=334\dfrac{45}{12} = \dfrac{15}{4} = 3\dfrac{3}{4}.

Common Mistakes

Mistake 1 — Adding whole numbers and fractions separately without converting

234+1232\frac{3}{4} + 1\frac{2}{3}: add whole parts (2+1=32+1=3) and fraction parts (34+23\frac{3}{4}+\frac{2}{3}) separately, then combine.

✅ This method works only when fraction parts don't exceed 1. When the fraction sum 1\geq 1, you must carry over to the whole number. Converting to improper fractions first avoids this trap.

Mistake 2 — Wrong multiplication in the conversion formula

325=3+25=553\frac{2}{5} = \frac{3+2}{5} = \frac{5}{5} (just adding instead of multiplying)

325=3×5+25=1753\frac{2}{5} = \frac{3 \times 5 + 2}{5} = \frac{17}{5} — multiply the whole number by the denominator first.

Mistake 3 — Forgetting to simplify after converting back

❌ Leaving an answer as 86\frac{8}{6} instead of simplifying.

✅ Always simplify: 86=43=113\frac{8}{6} = \frac{4}{3} = 1\frac{1}{3}.

Practice Problems

Problem 1: Convert 5385\dfrac{3}{8} to an improper fraction.

Show Answer

5×8+3=435 \times 8 + 3 = 43

438\dfrac{43}{8}

Problem 2: Convert 379\dfrac{37}{9} to a mixed number.

Show Answer

37÷9=437 \div 9 = 4 remainder 11

4194\dfrac{1}{9}

Problem 3: Calculate 312+2233\dfrac{1}{2} + 2\dfrac{2}{3}.

Show Answer

72+83=216+166=376=616\dfrac{7}{2} + \dfrac{8}{3} = \dfrac{21}{6} + \dfrac{16}{6} = \dfrac{37}{6} = 6\dfrac{1}{6}

Problem 4: Calculate 212×1452\dfrac{1}{2} \times 1\dfrac{4}{5}.

Show Answer

52×95=4510=92=412\dfrac{5}{2} \times \dfrac{9}{5} = \dfrac{45}{10} = \dfrac{9}{2} = 4\dfrac{1}{2}

Problem 5: Order from least to greatest: 2342\dfrac{3}{4}, 135\dfrac{13}{5}, 2122\dfrac{1}{2}.

Show Answer

Convert all to decimals: 2.752.75, 2.62.6, 2.52.5.

Order: 212<135<2342\dfrac{1}{2} < \dfrac{13}{5} < 2\dfrac{3}{4}

Summary

  • A mixed number combines a whole number and a proper fraction: abca\frac{b}{c}.
  • An improper fraction has numerator ≥ denominator: nd\frac{n}{d} where ndn \geq d.
  • Mixed → improper: multiply whole by denominator, add numerator, keep denominator.
  • Improper → mixed: divide numerator by denominator; quotient is whole, remainder is new numerator.
  • Use improper fractions when multiplying, dividing, or adding fractions with unlike denominators.

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