"It's complicated." I'm not LDS and haven't been a member of the Christian sect I was raised in for many years. I've had besties who were LDS, though, and we talked a lot whenever it came up in conversation. (Which tends to be surprisingly often, FWIW.)

The gist is that LDS members believe that the Bible is true when it has been correctly translated. But that's a gap big enough to drive a truck through. There are some very real irreconcilable differences between the Bible and the Book of Mormon.

For example, Mormons believe in the practice of "sealing"[0], which is basically marriage that lasts for eternity. However, Jesus himself explicitly says in the Bible[1] that this isn't so:

> The same day the Sadducees, who say there is no resurrection, came to Him and asked Him, saying: “Teacher, Moses said that if a man dies, having no children, his brother shall marry his wife and raise up offspring for his brother. Now there were with us seven brothers. The first died after he had married, and having no offspring, left his wife to his brother. Likewise the second also, and the third, even to the seventh. Last of all the woman died also. Therefore, in the resurrection, whose wife of the seven will she be? For they all had her.” Jesus answered and said to them, “You are mistaken, not knowing the Scriptures nor the power of God. For in the resurrection they neither marry nor are given in marriage, but are like angels of God in heaven.

Personally, it seems exceedingly unlikely to me that each one of the translations on the linked page are wrong in exactly the same way.

Anyway, that's why lots of LDS will say that they're Christians. If asked, they believe that the Bible is true where correctly translated, but in my (admittedly) limited experience, not many of them as a percentage have actually read the Bible themselves to know what it actually says about this. It's also why a lot of Christians say that LDS are not: they believe in lots of things that are not in the Bible, and believe that the Bible we have today has lots of mistakes.

[0]https://en.wikipedia.org/wiki/Sealing_(Mormonism)

[1]https://www.bible.com/bible/compare/MAT.22.23-30

NB: I'm not staking an opinion on any of this, or taking sides on the matter. I'm offering this in the same sense that I might share something I learned in history class about the French Revolution. It's interesting to read and learn about, but doesn't directly affect me and it's not anything I want to participate in. Especially do not take this chance to explain to me why the whole "left his wife to his brother" thing is f'ed up by modern standards.