Solve 1/10+4/5-1/20

$$\frac { 1 } { 10 } + \frac { 4 } { 5 } - \frac { 1 } { 20 }$$

Evaluate

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

Solution Steps

Least common multiple of 10 and 5 is 10. Convert \frac{1}{10} and \frac{4}{5} to fractions with denominator 10.

$$\frac{1}{10}+\frac{8}{10}-\frac{1}{20}$$

Since \frac{1}{10} and \frac{8}{10} have the same denominator, add them by adding their numerators.

$$\frac{1+8}{10}-\frac{1}{20}$$

Add 1 and 8 to get 9.

$$\frac{9}{10}-\frac{1}{20}$$

Least common multiple of 10 and 20 is 20. Convert \frac{9}{10} and \frac{1}{20} to fractions with denominator 20.

$$\frac{18}{20}-\frac{1}{20}$$

Since \frac{18}{20} and \frac{1}{20} have the same denominator, subtract them by subtracting their numerators.

$$\frac{18-1}{20}$$

Subtract 1 from 18 to get 17.

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

Factor

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