Lisa Marie Presley's Ex Says Her Math Is Way Off, She Can Pay for His Lawyers

Lisa Marie Presley is lying about the mountain of debt she claims to be under, and about how much money she's earning ... according to her estranged husband, Michael Lockwood ... TMZ has learned.

TMZ broke the story ... LMP says she's $16 million in the hole, and can't afford to pay Lockwood's attorney's fees -- but Lockwood ain't buying it. In docs he just filed, Lockwood says Elvis Presley's daughter sucks at math.

He points out she claimed to be making $104,000 per month in 2016, but also claimed she owed the IRS $1.67 million. Lockwood says that would mean she owes more than she made in income that year.

According to the docs, obtained by TMZ, Lisa Marie also fudged her numbers when she included the English manor she owns. Presley says she's way behind on the mortgage for it, but Lockwood says it's still worth something ... which she's left out of her calculations.

He's not backing off his demand for Lisa Marie to kick in for his lawyers to the tune of $450k.