7/15+9/17

Let's evaluate: $\frac{7}{15}+\frac{9}{17}$

ⓘ Add fractions by using a common denominator and then adding their numerators. We choose $255$, the least common multiple of $15$ and $17$. Multiplying the numerator and the denominator by the same number does not change the fraction: $\frac{7}{15}+\frac{9}{17}$ = $\frac{7\times 17}{15\times 17}+\frac{9\times 15}{17\times 15}$ = $\frac{7\times 17+9\times 15}{15\times 17}$

$\frac{7\times 17+9\times 15}{15\times 17}$

ⓘ Perform multiplications before additions and subtractions: $7\times 17$ = $7\times (10+7)$ = $7\times 10+7\times 7$ = $70+49$ = $119$, $9\times 15$ = $9\times (10+5)$ = $9\times 10+9\times 5$ = $90+45$ = $135$

ⅰ $15\times 17$ = $(10+5)\times 17$ = $10\times 17+5\times 17$ = $170+85$ = $255$

$\frac{119+135}{255}$

ⓘ Calculate the numerator and denominator before dividing: $119+135$ = $254$

▶Result:   $\frac{254}{255}$

The numeric value of: $\frac{254}{255}$ equals:

▷ $\approx 0.9961$