Помогите пожалуйста с Математикой, 6 класс:

1/3 - 1/6 =
3/20 + 3/4 =
7/9 - 2/3 =
1/4 + 1/5 =
2/5 + 4/15 =
1/3 + 1/4 =
2/3 - 2/5 =
1/5 - 1/6 =
1/2 + 1/4 =
7/6 - 1 =
1/2 + 2/7 =
1/2 - 1/3 =
3/4 + 1/8 =
5/6 - 7/12 =
2/5 + 3/10 =