Compare 21/42 and 18/20
21/42 is smaller than 18/20
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 42 × 10 = 420,
21/42 = 21 × 10/42 × 10 = 210/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
18/20 = 18 × 21/20 × 21 = 378/420 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 210/420 < 378/420 or 21/42 < 18/20
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