Solve -81/8+-31/20+7/10=

$$- 8 \frac { 1 } { 8 } + - 3 \frac { 1 } { 20 } + \frac { 7 } { 10 } =$$

Evaluate

$$-\frac{419}{40}=-10.475$$

Solution Steps

Multiply 8 and 8 to get 64.

$$-\frac{64+1}{8}-\frac{3\times 20+1}{20}+\frac{7}{10}$$

Add 64 and 1 to get 65.

$$-\frac{65}{8}-\frac{3\times 20+1}{20}+\frac{7}{10}$$

Multiply 3 and 20 to get 60.

$$-\frac{65}{8}-\frac{60+1}{20}+\frac{7}{10}$$

Add 60 and 1 to get 61.

$$-\frac{65}{8}-\frac{61}{20}+\frac{7}{10}$$

Least common multiple of 8 and 20 is 40. Convert -\frac{65}{8} and \frac{61}{20} to fractions with denominator 40.

$$-\frac{325}{40}-\frac{122}{40}+\frac{7}{10}$$

Since -\frac{325}{40} and \frac{122}{40} have the same denominator, subtract them by subtracting their numerators.

$$\frac{-325-122}{40}+\frac{7}{10}$$

Subtract 122 from -325 to get -447.

$$-\frac{447}{40}+\frac{7}{10}$$

Least common multiple of 40 and 10 is 40. Convert -\frac{447}{40} and \frac{7}{10} to fractions with denominator 40.

$$-\frac{447}{40}+\frac{28}{40}$$

Since -\frac{447}{40} and \frac{28}{40} have the same denominator, add them by adding their numerators.

$$\frac{-447+28}{40}$$

Add -447 and 28 to get -419.

$$-\frac{419}{40}$$

Factor

$$-\frac{419}{40} = -10\frac{19}{40} = -10.475$$