Heidi Klum -- Not a 10? I'll Show You, Donald Trump ... (VIDEO)

Heidi Klum concedes ... Donald Trump was right when he said she is "no longer a 10" -- but by Heidi's math, she's damn close.

Klum posted a funny response to the recent Trump diss, in a video featuring a guy in a Trump mask ripping off her "10" label to reveal she's now just ... a 9.99.

However you do the math, Heidi's still as hot as it gets.