Compare 15/28 and 20/21
15/28 is smaller than 20/21
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 28 × 3 = 84,
15/28 = 15 × 3/28 × 3 = 45/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
20/21 = 20 × 4/21 × 4 = 80/84 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 45/84 < 80/84 or 15/28 < 20/21
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