It's always best to use multiplicative factors rather than additive factors when doing these calculations.
Reinterpret a loss of 1/4 as a multiplier of 3/4 and a gain of 1/3 as a multiplier of 4/3.
Then you can take the V1 (3/4)(4/3) = V2 combining the two multiplicative steps
which shows that the final value is the same as the initial value.
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