Left had side:
70 + 2 = 72
72 + 0.3 = 72.3
72.3 + -30 is the same as 72.3 - 30 = 42.3
42.3 + -9 is the same as 42.3 - 9 = 33.3
33.3 + -0.1 is the same as 33.3 - 0.1 = 33.2
Right hand side:
70 + -30 is the same as 70 - 30 = 40
40 + 2 = 42
42 + -9 is the same as 42 - 9 = 33
33 + 0.3 = 33.3
33.3 + -0.1 is the same as 33.3 - 0.1 = 33.2
Therefore:
33.2 = 33.2
Which is true