Compare 21/40 and 15/42
21/40 is greater than 15/42
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 42 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
21/40 = 21 × 21/40 × 21 = 441/840 - Likewise, for the 2nd fraction, since 42 × 20 = 840,
15/42 = 15 × 20/42 × 20 = 300/840 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 441/840 > 300/840 or 21/40 > 15/42
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