Solve 9/10-(2/5+1/4)=

$$\frac { 9 } { 10 } - ( \frac { 2 } { 5 } + \frac { 1 } { 4 } ) =$$

Evaluate

$$\frac{1}{4}=0.25$$

Solution Steps

Least common multiple of 5 and 4 is 20. Convert \frac{2}{5} and \frac{1}{4} to fractions with denominator 20.

$$\frac{9}{10}-\left(\frac{8}{20}+\frac{5}{20}\right)$$

Since \frac{8}{20} and \frac{5}{20} have the same denominator, add them by adding their numerators.

$$\frac{9}{10}-\frac{8+5}{20}$$

Add 8 and 5 to get 13.

$$\frac{9}{10}-\frac{13}{20}$$

Least common multiple of 10 and 20 is 20. Convert \frac{9}{10} and \frac{13}{20} to fractions with denominator 20.

$$\frac{18}{20}-\frac{13}{20}$$

Since \frac{18}{20} and \frac{13}{20} have the same denominator, subtract them by subtracting their numerators.

$$\frac{18-13}{20}$$

Subtract 13 from 18 to get 5.

$$\frac{5}{20}$$

Reduce the fraction \frac{5}{20} to lowest terms by extracting and canceling out 5.

$$\frac{1}{4}$$

Factor

$$\frac{1}{2 ^ {2}} = 0.25$$