Compare 4/5 and 18/21
4/5 is smaller than 18/21
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 5 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 5 × 21 = 105,
4/5 = 4 × 21/5 × 21 = 84/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
18/21 = 18 × 5/21 × 5 = 90/105 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 84/105 < 90/105 or 4/5 < 18/21
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