13

24

36

43

54

45

47

18

30

(37)

Take 54 as the center

Then the left 54-43= 1 1, the right 54-45=9, 54-47=7, 45-47=-2, and the two sides make up 1 1.

No, then the left is not 54-24=30, 54-36= 18.

on the contrary

Further on, 24-(54-43)= 13 on the left.

Right 30+(54-47)=37

Further back

30+ 18=48

On the left is 13-(54-48)=7.