7/8-7/9

Let's calculate: $\frac{7}{8}-\frac{7}{9}$

ⓘ To add fractions, put them over the same denominator, then add the numerators. We choose $72$, the least common multiple of $8$ and $9$. Multiplying the numerator and the denominator by the same number does not change the fraction: $\frac{7}{8}-\frac{7}{9}$ = $\frac{7\times 9}{8\times 9}-\frac{7\times 8}{9\times 8}$ = $\frac{7\times 9-7\times 8}{8\times 9}$

$\frac{7\times 9-7\times 8}{8\times 9}$

ⓘ Perform multiplications before additions and subtractions: $7\times 9$ = $63$, $7\times 8$ = $56$

ⅰ $8\times 9$ = $72$

$\frac{63-56}{72}$

ⓘ Calculate the numerator and denominator before dividing: $63-56$ = $7$

▶Result:   $\frac{7}{72}$

The numeric value of: $\frac{7}{72}$ equals:

▷ $\approx 9.7222\times {10}^{-2}$