19/20-13/18

Let's calculate: $\frac{19}{20}-\frac{13}{18}$

ⓘ Add fractions by using a common denominator and then adding their numerators. We choose $180$, the least common multiple of $20$ and $18$. Multiplying the numerator and the denominator by the same number does not change the fraction: $\frac{19}{20}-\frac{13}{18}$ = $\frac{19\times 9}{20\times 9}-\frac{13\times 10}{18\times 10}$ = $\frac{19\times 9-13\times 10}{20\times 9}$

$\frac{19\times 9-13\times 10}{20\times 9}$

ⓘ Multiplications are done before additions and subtractions: $19\times 9$ = $(10+9)\times 9$ = $10\times 9+9\times 9$ = $90+81$ = $171$, $13\times 10$ = $(10+3)\times 10$ = $10\times 10+3\times 10$ = $100+30$ = $130$

ⅰ $20\times 9$ = $180$

$\frac{171-130}{180}$

ⓘ Calculate the numerator and denominator before dividing: $171-130$ = $41$

▶Result:   $\frac{41}{180}$

The numeric value of: $\frac{41}{180}$ equals:

▷ $\approx 0.2278$