Solve 9/10+3/20-3/15

$$\frac { 9 } { 10 } + \frac { 3 } { 20 } - \frac { 3 } { 15 }$$

Evaluate

$$\frac{17}{20}=0.85$$

Solution Steps

Least common multiple of 10 and 20 is 20. Convert \frac{9}{10} and \frac{3}{20} to fractions with denominator 20.

$$\frac{18}{20}+\frac{3}{20}-\frac{3}{15}$$

Since \frac{18}{20} and \frac{3}{20} have the same denominator, add them by adding their numerators.

$$\frac{18+3}{20}-\frac{3}{15}$$

Add 18 and 3 to get 21.

$$\frac{21}{20}-\frac{3}{15}$$

Reduce the fraction \frac{3}{15} to lowest terms by extracting and canceling out 3.

$$\frac{21}{20}-\frac{1}{5}$$

Least common multiple of 20 and 5 is 20. Convert \frac{21}{20} and \frac{1}{5} to fractions with denominator 20.

$$\frac{21}{20}-\frac{4}{20}$$

Since \frac{21}{20} and \frac{4}{20} have the same denominator, subtract them by subtracting their numerators.

$$\frac{21-4}{20}$$

Subtract 4 from 21 to get 17.

$$\frac{17}{20}$$

Factor

$$\frac{17}{2 ^ {2} \cdot 5} = 0.85$$