Can explain how the 4unit come from? And why it is 56 yellow bean is equal to 4unit ,
from my understanding is (56 yellow +9 red + 1unit =7/9)
, therefore (65 bead +1unit =7/9),,
Since (BLUE bead =2/9)
7-2= 65bead - blue bead + red bead added
5 unit = 65+ red bead added
Red bead added = 65/5 = 13 red beads??????

Can explain in a more simple easy understanding faction form, like how to convert faction to whole number??? Please help???

2/9 were blue meaning
2u are blue
7u are red + yellow
Since red is 3u
So, yellow is 4u, and yellow is 56
Therefore, 4u→56

Take note
2/5 refer to blue and red beans
2/9 refer to red, blue and yellow beans.

This ratio question with blue remain unchanged. Make sure blue is same unit, for this case, blue = 2u. So red = 3u

The answer = 42-9 =33
［Mistake on calculation :)］

Thank you very much, so need to use ratio method to solve this question, thank you, because I thought of using faction method but do not know how to convert to whole number ， thank you,
So red remains 3unit even when yellow bead is added, and so is Blue bead , which is also remain as 2 unit even when yellow bead is added.. but in the faction method, the denominator changes from 2/5 to 2/9 , thought the top numerator remain the same for blue bead only, thank you