“Mathematics is made of 50 percent formulas, 50 percent proofs and 50 percent imagination” is a math joke—the percentages add up to 150 percent, not 100 percent. The joke was printed in Pi in the Sky (June 2001) by The Pacific Institute for the Mathematical Sciences (Alberta, Canada).
 
Authorship of the joke is unknown.
 
     
The Pacific Institute for the Mathematical Sciences (Alberta, Canada)
June 2001
Pi in the Sky
Pg. 14, col. 2:
Mathematics is made of 50 percent formulas, 50 percent proofs and 50 percent imagination.
 
Google Groups: sci.math.research
Dimensions of Fractal like sets question.
Adam Ringler
7/8/02
(...)
Mathematics is made of 50 percent formulas, 50 percent proofs and 50 percent imagination.
   
Google Groups: humanities.philosophy.objectivism
The Non-Aggression Axiom of Libertarianism
TommCatt
2/20/03
(...)
Mathematics is made of 50 percent formulas, 50 percent proofs and 50 percent imagination.
         
Twitter
Ascend Education
@AscendEducation
“Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination.”
9:32 AM · May 5, 2009·Twitter Web Client
 
Top 100
SATURDAY, JULY 11, 2009
Top 10’s Funny Mathematics Quotes
(...)
“Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination.”
 
Twitter
School of Mathematics
@MathsBirmingham
#Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent #imagination. #mathsbirmingham #quotes
Image
1:41 PM · Dec 20, 2012 from Birmingham, England·Tweetbot for iOS
   
Google Books
Olympiad EHF Math Activity Book Class 7
Edited by Dr. Sandeep Ahlawat
Delhi, India: EHF Learning Media Pvt Ltd.
2014
Pg. 25:
Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination.
 
Quora
Is this true: “Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination”?
Kurt Behnke, PHD Mathematics & Physics, University of Hamburg (1981)
Answered Mar 2, 2018
First exercise in mathematics: add correctly. 50% of A plus 50% of B plus 50% of C make 150%, not 100.
 
Then: that is way too formalistic. Formulas play a much smaller role in math, than most laypeople actually believe. Algebraic calculation is a basic skill needed for most of math, and some are better than others, but it is not a central capability that constitutes a mathematicians. Personally I always had the impression, that for example theoretical physicists were much better at formula calculations than me and my math colleagues.
 
Frank SMS
15 Hilarious Quotes About Math
FrankSMS.com July 16, 2018  
(...)
15. Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination
~ Unknown
Did they just miss the whole point? Or is that the whole point? Does this mean whatever answer we come up with is the right one? Yes, let’s go with that.
 
Twitter
Pete Cumberland
@petercumberland
Replying to @InternotLimited and @MadSossy
Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination. An engineer thinks that his equations are an approximation to reality. A physicist thinks reality is an approximation to his equations. A mathematician doesn’t care.
1:00 AM · May 26, 2019·Twitter Web Client