Compare 9/21 and 15/20
9/21 is smaller than 15/20
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
9/21 = 9 × 20/21 × 20 = 180/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
15/20 = 15 × 21/20 × 21 = 315/420 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 180/420 < 315/420 or 9/21 < 15/20
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