ANSWER
\dfrac{1}{5}
EXPLANATION
Based on the given conditions, formulate: \dfrac{9}{10} - \dfrac{7}{10} 
Write the numerators over common denominator:\dfrac{9 - 7}{10}
Calculate the sum or difference:\dfrac{2}{10}
Reduce the fraction:\dfrac{1}{5}
Convert to fraction: \dfrac{1}{5}
Answer: \dfrac{1}{5}
Based on the given conditions, formulate: 
Write the numerators over common denominator:
Calculate the sum or difference:
Reduce the fraction:
Convert to fraction: 
Answer: