Rename dividing decimals to dividing decimals 4
Retitle file
Dividing an integer by simple decimal
Include decimals representing mutliples of a quarter
Dividing decimals 3 exercise
Start dividing decimals 2
lint on solid_geometry, created volume_1
ensure that one of the numbers has a imaginary component

example: [adding_and_subtracting_complex_numbers.html?seed=120](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/adding_and_subtracting_complex_numbers.html?seed=120&problem=0&debug)
improve hints: fix #58118
consistent punctuation

end sentence with a punctuation
add missing closing span tag, fix: #58083
Change answer type to regex
Use expression editor for complex number questions
Remove complexRegex function as it's not needed any more
Merge remote-tracking branch 'upstream/master' into div-dec
Dividing decimals 2 - some times the answer is a decimal
More changes...
Added a "sketch" to graphie-3d  for 3d line drawings.
Put the line height on the math holders

Summary: If we put line-heights on things inside, sometimes it overrides
the line-height of the math itself (which messes things up). Fixes
T1280

Auditors: alpert
Merge pull request #58394 from mauk81/patch-1

add missing closing span tag, fix: #58083