Answer :

First, divide 1 by 3 and 1 by 2.

1 divided by 3 = 0.33333333333

1 divided by 2 = 0.5

Add them up. 
0.33333333333 + 0.5 = 0.83333333333.

Divide 
0.83333333333 by 2, since there are 2 numbers we added up. 0.83333333333 / 2 = 0.41666666666, and 0.41666666666 as a fraction is 5/12.
1/3 = 2/6
1/2 = 3/6

Since there is no integer between 2 and 3, we must do some more working out;

1/3 = 2/6 = 4/12
1/2 = 3/6 = 6/12

The numerators (4 and 6) are both whole numbers and we know that 5 is between them, meaning that;

5/12 is bigger than 4/12 but smaller than 6/12

5/12 is between 1/3 and 1/2