JavaScript's Unique Approach to Basic Arithmetic

Description

This meme uses the 'Woman Showing Paper to a Cat' format. The top part of the image contains a text exchange: 'Teacher: How much is 1.1 * 3 ?', 'He: 3.3', 'Teacher: Then why did you write 3.3000000000000003 ?'. The bottom panel shows a woman looking at a paper with a small grey cat, and a zoomed-in image of the cat looking stressed and guilty. The cat is labeled 'JavaScript developer'. The humor stems from a well-known quirk in JavaScript (and other languages using IEEE 754 floating-point arithmetic) where simple decimal calculations result in precision errors. The expression `1.1 * 3` evaluates to the long decimal because of how these numbers are represented in binary. The meme personifies this language flaw as a developer being caught making a fundamental math error, perfectly capturing the frustrating and often comical nature of floating-point inaccuracies

Common Tags

Javascript FloatingPointPrecision LanguageQuirks FloatingPointArithmetic DeveloperHumor CodingHumor SubtleBugs

Comments

Anonymous ★ Top Pick This is why we have a `===` operator. One equals is for the value, one is for the type, and the third is to check if the floating-point representation is having an existential crisis

Anonymous ★ Top Pick

This is why we have a `===` operator. One equals is for the value, one is for the type, and the third is to check if the floating-point representation is having an existential crisis
Anonymous

PM: “Can we stop showing 3.3000000000000003 on the invoice?” Me: “Sure - just budget a sprint to replace IEEE-754, every browser VM, and probably a few laws of physics.”
Anonymous

After 20 years in the industry, you learn that the real skill isn't avoiding floating-point errors - it's explaining to the finance team why their quarterly reports are off by 0.0000000000000003 cents and convincing them it's actually the computer being mathematically correct
Anonymous

Every JavaScript developer has had that moment explaining to a stakeholder why their financial calculations are off by 0.0000000000000003. 'It's not a bug, it's IEEE 754!' we cry, while frantically googling decimal.js libraries and wondering why we didn't just use integers and store everything in cents like the backend team suggested three sprints ago
Anonymous

I didn’t fail math - I passed IEEE‑754: 3.3 is a UI concern; 3.300000000000003 is the backend truth
Anonymous

In JavaScript, 1.1*3 equals an IEEE‑754 footnote, a decimal library, and an awkward finance call
Anonymous

Because JS multiplies like microservices: distributed accuracy with consistency eventually
@lord_nani 5y

why exclusively js?
1. @metal_Dash 5y
  
  Yes
@maxgraey 5y

https://0.30000000000000004.com/
1. @doorhinge 5y
  
  brilliant
@maxgraey 5y

When you hate JS for 0.1+0.2 != 0.3 you should in the same way hate Rust, C++, python, Haskell, your CPU and at last William Kahan)
1. @asm3r 5y
  
  +1.
@ynsgnr 5y

Floating point errors are really something
@zherud 5y

is there a language where 1.1*3 is actually 3.3?
1. Deleted Account 5y
  
  haskell and lisp
  
  Deleted Account 5y
  
  they use fractions and floats
  
  @zherud 5y
  
  and how are there 1.1*3=3.3?
  
  @bit69tream 5y
  
  common lisp (sbcl) * (* 1.1 3) 3.3000002 haskell Prelude> 1.1 * 3 3.3000000000000003
  
  Deleted Account 5y
  
  if you do the 11 % 10
  
  @bit69tream 5y
  
  ?
  
  Deleted Account 5y
  
  represent 1.1 as rational
  
  @bit69tream 5y
  
  * (float (* (rationalize 1.1) 3)) 3.3
  
  Deleted Account 5y
  
  ye like this it's gonna produce trash
  
  @asm3r 5y
  
  Sbcl: (/ 3 10) 3/10
2. @Araalith 5y
  
  Even IRL 1.1*3 can be 3.2999(9)
@dr_f33lg00d 5y

python kek
@firs_iln 5y

fukkk whyyy