Then I noticed that the examples have the same denominator. Pupils encountered these examples in the first grade. After this exercise, the teacher wrote an example on the board: 3/4 + 5/6 =. The teacher asked the students how they would solve the example. He deliberately had the students write a mistake on the board (3/4 + 5/6 = / (4 + 6)) and then showed them why they couldn't do it that way.
After this exercise, the teacher wrote an example on the board: 3/4 + 5/6 =.