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FractionsArithmeticElementary schoolabout 0:53

Calculate 9/7 - 8/3: animated lesson

A narrated, step-by-step fractions video lesson with captions. Final answer: -29/21.

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Video with a synthetic English voice and captions. Pick another language for subtitles in that language, or open the interactive version.

Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.3 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Worked example
9/7 - 8/3
2. Step by step
1. $\frac{9}{7} - \frac{8}{3} = \frac{27}{21} - \frac{56}{21}$
  Rewrite both fractions with the least common denominator
2. $\frac{27 - 56}{21} = -\frac{29}{21}$
  Subtract the numerators and keep the denominator
3. $-\frac{29}{21} = -1\tfrac{8}{21}$
  Final answer in lowest terms
3. The answer
$-\frac{29}{21}$
9/7 - 8/3 = -29/21
4. Check
- Decimal check: -29/21 ≈ -1.380952381
- As a mixed number: -1 8/21

Transcript

The problem. Here is the problem: 9 over 7 minus 8 over 3. Exact arithmetic with fractions (results kept in lowest terms).

Step by step. Rewrite both fractions with the least common denominator. The LCD of 7 and 3 is 21. Subtract the numerators and keep the denominator. Final answer in lowest terms.

The answer. So the answer is negative 29 over 21. Fractions are combined over a common denominator for addition and subtraction, multiplied straight across, and divided by multiplying by the reciprocal. The result is reduced by the greatest common factor.

Check. Decimal check: negative 29 over 21 approximately negative 1.380952381. As a mixed number: negative 1 8 over 21.

About fractions

Add, subtract, multiply and divide fractions, finding common denominators and simplifying the result.

Calculate 9/7 - 8/3: Fractions Step-by-Step Lesson