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Fractions-DECODED!

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Naming Fractions I

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Reciprocal

Expanding Fractions I

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Simplifying Fractions I

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Simplifying Fractions III

Simplifying Fractions IV

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Prime Numbers

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Adding Fractions

Adding Mixed Numbers

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Subtract the two fractions.

Two fractions are subtracted by expanding them to the common denominator and then subtracting their numerators.

Check whether the result can be simplified.

If you would like to have a vivid explanation with a detailed example, please read the page Subtraction Fraction minus Fraction - The Thought Experiment

**Step 1: Determine the common denominator:**

The common denominator is equal to the lowest common multiple (LCM) of the two denominators: **42** (open here)

1) In order to calculate the least common multiple (LCM) of 14 and 21, you need the greatest common divisor (GCD) first:

14 ÷ 21 = 0 Remainder 14

21 ÷ 14 = 1 Remainder 7

14 ÷ 7 = 2 Remainder 0

The Greatest Common Divisor (GCD) of 14 and 21 is **7**.

2) The least common multiple (LCM) is calculated by multiplying the two numbers and then dividing by the greatest common divisor (GCD). It's easier if you first divide and then multiply:

14 × (21 : 7) = 14 × 3 = 42

**Step 2: Expand to the common denominator:**

Expand the first fraction with the number 3 and the second fraction with the number 2.

11 | - | 11 | = | 11 × 3 | - | 11 × 2 | = | 33 | - | 22 |

14 | 21 | 14 × 3 | 21 × 2 | 42 | 42 |

**Step 3: Subtract the numerators:**

Since the two fractions have a common denominator, you can subtract:

33 | - | 22 | = | 33 - 22 | = | 11 |

42 | 42 | 42 | 42 |

**Step 4: Check whether the result can be simplified**

The result can not be simplified.