Coming across these kind of constructs:
カニでもわかる＋名詞句
カニでもできる...
カニでも使える...
etc.
What does it mean? How is it used?
In general, what main associations would a "crab" create from a Japanese cultural perspective? E.g. lion - brave; tanuki - sly; crab - ???
I personally didn't know the very exact expression, but I can make a reasonable guess that it's a variant of サルでも…… ("Even monkeys do..."). The implication is quite similar to "for dummies" in English, which is to state its easiness in exaggerated manner.
One of web pages using the phrase declares:
昔、サルでもわかるナントカってのがありましたが、その上をいきます。カニでも分かる簿記！ホ乳類じゃなくても大丈夫！
There were some (books?) like "~~ For Monkeys" quite some time ago, but we'll go much farther. Bookkeeping For Crabs! You don't even need to be a mammal!
By the way I'd like to add that my favorite one is ヤドンでもできるポケモン乱数調整 ("Pokémon RNG Manipulation for Slowpokes").
