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1. Slash like this "/" is used in Math to symbolize the division operation.
2. If you want symbolize something different (I suppose, you want to symbolize "the absolute value") then at least say it by words.
3. Actually, the computer keyboard has the symbol "absolute value". It is this vertical stick, "|".
4. But if you sent your post from your phone, you may have problems.
If so, then use the advise in #2.