Must be equal to e mail

I see what you're getting at!

Yes, "must be equal to" is often abbreviated as "MUST BE = TO" or simply "MBET" in informal writing, such as text messages, emails, or social media posts.

However, in formal writing, such as academic papers, articles, or official documents, it's more common to use the full phrase "must be equal to" or "is equal to" instead of an abbreviation.

So, while "MBET" might be a convenient shortcut in casual communication, it's not typically used in formal writing.