Question

Simplify the expression -7/9 - 5/10

Answer 1

We can sum two fractions if they have the same denominator, so we have to rewrite both fractions so that they'll have the same denominator.

We can generate equivalent fractions by multiplying both numerator and denominator by the same number.

So, we have

$-\dfrac{7}{9} = -\dfrac{7\cdot 10}{9\cdot 10} = -\dfrac{70}{90}$

Similarly, we have

$-\dfrac{5}{10} = -\dfrac{5\cdot 9}{10\cdot 9} = -\dfrac{45}{90}$

Now we can sum the fractions:

$-\dfrac{7}{9}-\dfrac{5}{10} = -\dfrac{70}{90}-\dfrac{45}{90} = \dfrac{-70-45}{90} = -\dfrac{115}{90} = -\dfrac{23}{18}$