Source: http://www.xkcd.com/1047/
Tag: xkcd
Forgot algebra
Source: http://www.xkcd.com/1050/
Depth perception
Source: http://www.xkcd.com/941/
Percentage points
Password strength and combinatorics
Source: http://www.xkcd.com/936/
Binary
Source: http://www.xkcd.com/953/
Formal logic bumper sticker
Source: http://www.xkcd.com/1033/
Paths
I offer the following xkcd comic as a possible engagement exercise concerning the Pythagorean theorem.
Source: http://www.xkcd.com/85/
Null hypothesis
Source: http://xkcd.com/892/
Importance of labeling axes
Source: http://www.xkcd.com/833/
Mean Green Math 