Add 21/42 and 40/90
21/42 + 40/90 is 17/18.
Steps for adding 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,
40/90 = 40 × 7/90 × 7 = 280/630 - Add the two like fractions:
315/630 + 280/630 = 315 + 280/630 = 595/630 - 595/630 simplified gives 17/18
- So, 21/42 + 40/90 = 17/18
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