Solve -15/8-(-21/5)

$$- 1 \frac { 5 } { 8 } - ( - 2 \frac { 1 } { 5 } )$$

Evaluate

$$\frac{23}{40}=0.575$$

Solution Steps

Multiply 1 and 8 to get 8.

$$-\frac{8+5}{8}-\left(-\frac{2\times 5+1}{5}\right)$$

Add 8 and 5 to get 13.

$$-\frac{13}{8}-\left(-\frac{2\times 5+1}{5}\right)$$

Multiply 2 and 5 to get 10.

$$-\frac{13}{8}-\left(-\frac{10+1}{5}\right)$$

Add 10 and 1 to get 11.

$$-\frac{13}{8}-\left(-\frac{11}{5}\right)$$

The opposite of -\frac{11}{5} is \frac{11}{5}.

$$-\frac{13}{8}+\frac{11}{5}$$

Least common multiple of 8 and 5 is 40. Convert -\frac{13}{8} and \frac{11}{5} to fractions with denominator 40.

$$-\frac{65}{40}+\frac{88}{40}$$

Since -\frac{65}{40} and \frac{88}{40} have the same denominator, add them by adding their numerators.

$$\frac{-65+88}{40}$$

Add -65 and 88 to get 23.

$$\frac{23}{40}$$

Factor

$$\frac{23}{2 ^ {3} \cdot 5} = 0.575$$