Add 80/21 and 21/72, Solve 3 17/21 + 21/72 as a fraction

Add 80/21 and 21/72

1^st number: 3 17/21, 2^nd number: 21/72

80/21 + 21/72 is 689/168.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 72 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 21 × 24 = 504,
80/21 = 80 × 24/21 × 24 = 1920/504
Likewise, for the 2nd fraction, since 72 × 7 = 504,
21/72 = 21 × 7/72 × 7 = 147/504
Add the two like fractions:
1920/504 + 147/504 = 1920 + 147/504 = 2067/504
2067/504 simplified gives 689/168
So, 80/21 + 21/72 = 689/168
In mixed form: 417/168

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