Compare 21/42 and 18/40
21/42 is greater than 18/40
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 42 × 20 = 840,
21/42 = 21 × 20/42 × 20 = 420/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
18/40 = 18 × 21/40 × 21 = 378/840 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 420/840 > 378/840 or 21/42 > 18/40
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