Solve (70/80-30/40)+3/10

$$( \frac{ 70 }{ 80 } - \frac{ 30 }{ 40 } )+ \frac{ 3 }{ 10 }$$

Evaluate

$$\frac{17}{40}=0.425$$

Solution Steps

Reduce the fraction \frac{70}{80} to lowest terms by extracting and canceling out 10.

$$\frac{7}{8}-\frac{30}{40}+\frac{3}{10}$$

Reduce the fraction \frac{30}{40} to lowest terms by extracting and canceling out 10.

$$\frac{7}{8}-\frac{3}{4}+\frac{3}{10}$$

Least common multiple of 8 and 4 is 8. Convert \frac{7}{8} and \frac{3}{4} to fractions with denominator 8.

$$\frac{7}{8}-\frac{6}{8}+\frac{3}{10}$$

Since \frac{7}{8} and \frac{6}{8} have the same denominator, subtract them by subtracting their numerators.

$$\frac{7-6}{8}+\frac{3}{10}$$

Subtract 6 from 7 to get 1.

$$\frac{1}{8}+\frac{3}{10}$$

Least common multiple of 8 and 10 is 40. Convert \frac{1}{8} and \frac{3}{10} to fractions with denominator 40.

$$\frac{5}{40}+\frac{12}{40}$$

Since \frac{5}{40} and \frac{12}{40} have the same denominator, add them by adding their numerators.

$$\frac{5+12}{40}$$

Add 5 and 12 to get 17.

$$\frac{17}{40}$$

Factor

$$\frac{17}{2 ^ {3} \cdot 5} = 0.425$$