Ripping in order to fix is קורע, as in the mishkan they ripped curtain that worms had made holes inside before repairing them.

Even just stretching a thread to tighten connection between two pieces of garment is a form of sewing.

It is forbidden to converse with a heretic. It is not forbidden to converse with a sorcerer.

It is a mitzvah to engage in astronomy and other science in order to gain deeper appreciation of Hashem.

Acc to r Yehuda, squeezing out blood from a snail/fish is a form of דישה. However, the rabbis hold that אין דישה אלא בגידולי קרקע.

Squeezing out blood from a snail to extract the dye is not forbidden under נטילת נשמה bc the one squeezing is disinterested in killing the snail. If anything, they prefer it to live so the dye will be clear color.

Acc to rav, one who slaughters an animal is also performing צובע- dying- bc they are interested in making the hide red so ppl will be more excited to buy meat. This is in addition to the melocho of killing- נטילת נשמה.

Salting Hides is not its own melocho; it’s jsut a form of tanning, that is מעבד.

There’s an additional melocho called שירטוט- tracing lines in skin to prepare them for cutting.

If someone salts meat heavily to preserve it for travel, it’d a dispute if that’s called tanning or if perhaps foods are exempt from tanning.

Dressing a wound on Shabbos cns be ממחק- smoothing.

Any final touch on a kli is מכה בפטיש. Like coloring a picture on a kli, blowing glass, removing protruding threads form a garment.

Writing two letters is כותב. Erasing in order to write is כותב- even erasing jsut one letter in order to write two in its space.

A toldah and av only requires one Korban, while r Eliezer says it’s requires two.

R yehuda adds two additional melochos by setting up the threads of the loom and flattening the threads so they fit though, but the rabanan say it’s included in the other melochos of the loom.