When Walt drops the plate, none of the pieces are in the shape Crazy-8 keeps.
At the end, Walt is sitting in his car on an overpass above a divided highway. From inside the car, you clearly see that he is positioned over one side of the divided highway, with vehicles zooming by directly beneath him. But when the camera cuts to an exterior view just before he starts his engine, his car is now over the wide, grass divider, nowhere near directly above either side of the freeway.
When Walter drops the yellow plate, it breaks into several pieces of roughly the same size. In a subsequent shot, one fragment of the plate is now shattered into much smaller pieces.
When Walter is done cleaning up the broken plate, there is what looks like a single potato chip left in the middle of the blood stain on the floor. In subsequent shots, the chip is gone.
When Jesse and Walt are arguing in Jesse's driveway, the strings on Jesse's coat change lengths between shots.
On top of the pieces of the broken plate changing size and none of them matching the piece that Crazy 8 took, none of the pieces are missing off of the floor between Walter passing out and waking back up.
Marie uses the word "infer" when she meant to use "imply".
Walter and Gretchen add up the proportion of elements that make up the human body (by mole, not by mass). They get 63% hydrogen, 26% oxygen, 9% carbon, nitrogen 1.25%, and so on. These numbers themselves are mostly correct. What is incorrect is how they added up the numbers. When adding up numbers, you should base the answer on the number with the least amount of precision. He got 99.888042%. He should have rounded up his final answer to the ones digit to get 100%. Walt, as a scientist and as a chemistry teacher, should have known better.