Solve (1/5+1/4)-1/20=

$$( \frac { 1 } { 5 } + \frac { 1 } { 4 } ) - \frac { 1 } { 20 } =$$

Evaluate

$$\frac{2}{5}=0.4$$

Solution Steps

Least common multiple of 5 and 4 is 20. Convert \frac{1}{5} and \frac{1}{4} to fractions with denominator 20.

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

Since \frac{4}{20} and \frac{5}{20} have the same denominator, add them by adding their numerators.

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

Add 4 and 5 to get 9.

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

Since \frac{9}{20} and \frac{1}{20} have the same denominator, subtract them by subtracting their numerators.

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

Subtract 1 from 9 to get 8.

$$\frac{8}{20}$$

Reduce the fraction \frac{8}{20} to lowest terms by extracting and canceling out 4.

$$\frac{2}{5}$$

Factor

$$\frac{2}{5} = 0.4$$