Answer :

Make sure they have all common denominators
[tex] \frac{2}{4} + \frac{4}{5} - \frac{7}{10} [/tex]

[tex] \frac{2}{4} * \frac{5}{5} = \frac{10}{20} [/tex]

[tex] \frac{4}{5} * \frac{4}{4} = \frac{16}{20} [/tex]

[tex] \frac{7}{10} * \frac{2}{2} = \frac{14}{20} [/tex]

[tex] \frac{10}{20} + \frac{16}{20} - \frac{14}{20} [/tex]

Add [tex] \frac{10}{20} + \frac{16}{20} = \frac{26}{20} [/tex]
[tex] \frac{26}{20} - \frac{14}{20} = \frac{12}{20} [/tex]

To simplify, you must find the largest common factor which 4
In [tex] \frac{12}{20} [/tex]
12÷4=3 and 20÷4=5

The answer is [tex] \frac{3}{5} [/tex]