Compare 21/42 and 30/90
21/42 is greater than 30/90
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 42 × 15 = 630,
21/42 = 21 × 15/42 × 15 = 315/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
30/90 = 30 × 7/90 × 7 = 210/630 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 315/630 > 210/630 or 21/42 > 30/90
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