Solve 15-[7-(21/4+17/8)]

$$15 - [ 7 - ( 2 \frac { 1 } { 4 } + 1 \frac { 7 } { 8 } ) ]$$

Evaluate

$$\frac{97}{8}=12.125$$

Solution Steps

Multiply 2 and 4 to get 8.

$$15-\left(7-\left(\frac{8+1}{4}+\frac{1\times 8+7}{8}\right)\right)$$

Add 8 and 1 to get 9.

$$15-\left(7-\left(\frac{9}{4}+\frac{1\times 8+7}{8}\right)\right)$$

Multiply 1 and 8 to get 8.

$$15-\left(7-\left(\frac{9}{4}+\frac{8+7}{8}\right)\right)$$

Add 8 and 7 to get 15.

$$15-\left(7-\left(\frac{9}{4}+\frac{15}{8}\right)\right)$$

Least common multiple of 4 and 8 is 8. Convert \frac{9}{4} and \frac{15}{8} to fractions with denominator 8.

$$15-\left(7-\left(\frac{18}{8}+\frac{15}{8}\right)\right)$$

Since \frac{18}{8} and \frac{15}{8} have the same denominator, add them by adding their numerators.

$$15-\left(7-\frac{18+15}{8}\right)$$

Add 18 and 15 to get 33.

$$15-\left(7-\frac{33}{8}\right)$$

Convert 7 to fraction \frac{56}{8}.

$$15-\left(\frac{56}{8}-\frac{33}{8}\right)$$

Since \frac{56}{8} and \frac{33}{8} have the same denominator, subtract them by subtracting their numerators.

$$15-\frac{56-33}{8}$$

Subtract 33 from 56 to get 23.

$$15-\frac{23}{8}$$

Convert 15 to fraction \frac{120}{8}.

$$\frac{120}{8}-\frac{23}{8}$$

Since \frac{120}{8} and \frac{23}{8} have the same denominator, subtract them by subtracting their numerators.

$$\frac{120-23}{8}$$

Subtract 23 from 120 to get 97.

$$\frac{97}{8}$$

Factor

$$\frac{97}{2 ^ {3}} = 12\frac{1}{8} = 12.125$$