Solve 21/28+8/15-21/30

$$21 / 28 + 8 / 15 - 21 / 30$$

Evaluate

$$\frac{7}{12}\approx 0.583333333$$

Solution Steps

Reduce the fraction \frac{21}{28} to lowest terms by extracting and canceling out 7.

$$\frac{3}{4}+\frac{8}{15}-\frac{21}{30}$$

Least common multiple of 4 and 15 is 60. Convert \frac{3}{4} and \frac{8}{15} to fractions with denominator 60.

$$\frac{45}{60}+\frac{32}{60}-\frac{21}{30}$$

Since \frac{45}{60} and \frac{32}{60} have the same denominator, add them by adding their numerators.

$$\frac{45+32}{60}-\frac{21}{30}$$

Add 45 and 32 to get 77.

$$\frac{77}{60}-\frac{21}{30}$$

Reduce the fraction \frac{21}{30} to lowest terms by extracting and canceling out 3.

$$\frac{77}{60}-\frac{7}{10}$$

Least common multiple of 60 and 10 is 60. Convert \frac{77}{60} and \frac{7}{10} to fractions with denominator 60.

$$\frac{77}{60}-\frac{42}{60}$$

Since \frac{77}{60} and \frac{42}{60} have the same denominator, subtract them by subtracting their numerators.

$$\frac{77-42}{60}$$

Subtract 42 from 77 to get 35.

$$\frac{35}{60}$$

Reduce the fraction \frac{35}{60} to lowest terms by extracting and canceling out 5.

$$\frac{7}{12}$$

Factor

$$\frac{7}{2 ^ {2} \cdot 3} = 0.5833333333333334$$