Convert the denominator of the first two fractions to 24 since 3 and 8 can fit into 24.
3/8=9/24
2/3=16/24
Now add them together.
9/24+16/24=25/24
Next add the second two fractions 9/24 and 16/24.
9/24+16/24=25/24
Since all fractions equal 25/24, the equation was true!
Hope this helps!