To correct the student's answer

Image from preview.redd.it and submitted by SayLittleDoMuch
image showing To correct the student's answer

Mutzart on May 20th, 2019 at 14:39 UTC »

Time to make the teacher saw boards into 1 piece... and watch the teacher think about it for 5 minutes !

idlesn0w on May 20th, 2019 at 16:10 UTC »

Pretty impressive that Marie can cut a board into 1 piece in only 5 minutes.

Logofascinated on May 20th, 2019 at 16:46 UTC »

Fellow programmers will recognise this as a Fencepost Error variant.

"If you build a straight fence 30 meters long with posts spaced 3 meters apart, how many posts do you need?"

The naive answer 10 is wrong. The fence has 10 sections, but 11 posts.