Add 20/21 and 15/90
20/21 + 15/90 is 47/42.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 21 × 30 = 630,
20/21 = 20 × 30/21 × 30 = 600/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
15/90 = 15 × 7/90 × 7 = 105/630 - Add the two like fractions:
600/630 + 105/630 = 600 + 105/630 = 705/630 - 705/630 simplified gives 47/42
- So, 20/21 + 15/90 = 47/42
In mixed form: 15/42
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