Solve 1/frac{1{18}-1/21}=

$$\frac { 1 } { \frac { 1 } { 18 } - \frac { 1 } { 21 } } =$$

Evaluate

$$126$$

Solution Steps

Least common multiple of 18 and 21 is 126. Convert \frac{1}{18} and \frac{1}{21} to fractions with denominator 126.

$$\frac{1}{\frac{7}{126}-\frac{6}{126}}$$

Since \frac{7}{126} and \frac{6}{126} have the same denominator, subtract them by subtracting their numerators.

$$\frac{1}{\frac{7-6}{126}}$$

Subtract 6 from 7 to get 1.

$$\frac{1}{\frac{1}{126}}$$

Divide 1 by \frac{1}{126} by multiplying 1 by the reciprocal of \frac{1}{126}.

$$1\times 126$$

Multiply 1 and 126 to get 126.

$$126$$

Factor

$$2\times 3^{2}\times 7$$