Obtain the truth value of

(i)
If 5 + 6 = 11, then 11 – 6 = 5.

(ii)
If 5 + 8 = 12, then 12 + 8 = 20.

(iii)
If 6 + 9 = 14, then 14 – 7 = 8

(iv)
If 7 + 8 = 15, then 8 – 7 = 2
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