Rounding problems with calculate numbers in Javascript [duplicate] - javascript

This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 8 years ago.
I've got the following problem when i'm counting in javascript.
var processAmount = parseFloat(166.98) - parseFloat(61.58);
The result is: 105.39999999999999
Doesnt matter if I use parseFloat() or not.
How can I solve this?

Sometimes floats numbers cannot be represented exactly in binary.
Try this:
var processAmount = parseFloat(166.98) - parseFloat(61.58);
processAmount.toFixed(2);
FROM: Javascript float subtract

Related

What's the deal with big number faulty arithematic in JS? [duplicate]

This question already has answers here:
What is JavaScript's highest integer value that a number can go to without losing precision?
(21 answers)
Large numbers erroneously rounded in JavaScript
(6 answers)
javascript large integer round because precision? (why?)
(2 answers)
Closed 1 year ago.
So, I found something I couldn't understand and can't find any internet resource that explains it.
Please see the code below:
var num = 35422484817926290
// subtract 5 from num
console.log(num-5)
Output (Wrong) : 35422484817926284
I checked it in Node, Opera, and Chrome, all of them give the wrong answers.
I do understand the fact that arithmetic with unsafe Integers in JS is faulty, for example:
console.log(100000000000000005-1)
Output (Wrong) : 100000000000000000
So what's the deal with big number arithmetic in JS?
When I run this code:
var num = 35422484817926290
// subtract 5 from num
console.log(num-5)
in Visual Studio Code, i get the following warning:
"Numeric literals with absolute values equal to 2^53 or greater are too large to be represented accurately as integers."
So the correct way to make this calculation would be like this:
var num = 35422484817926290n
// subtract 5 from num
console.log(num-5n)
JavaScript is not faulty, this is how the Floating point arithmetic works. Looks duplicate to this post. For better calculation involving floating-point numbers you should use BigNumber API.

javascript - toFixed covert problem in (444.2).toFixed(14) [duplicate]

This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 1 year ago.
as the title
when I use toFixed to convert the float
(0.2).toFixed(4) -> 0.2000
(444.2).toFixed(4) -> 444.2000
(0.2).toFixed(14) -> 0.20000000000000
(444.2).toFixed(14) -> 444.19999999999999 //why ?!!!
I could not understand that what causes this result.
Is any javascript method to avoid this problem?
Floating point numbers cannot represent all decimals precisely in binary. one way to overcome this problem is using parseFloat:
console.log(parseFloat((444.2).toFixed(14)));

Javascript: Subtracting a whole integer from a integer with a decimal alters the decimal value? [duplicate]

This question already has answers here:
Is floating point math broken?
(31 answers)
Get decimal portion of a number with JavaScript
(29 answers)
Closed 3 years ago.
The goal is to isolate the decimal value (with simply turning the integer into a string and splitting it).
To that affect I have:
var x = 1001.1;
var roundedDown = Math.floor(x); // Produces 1001
var decimal = x - roundedDown;
The expected value of decimal should be 0.1 (1001.1 - 1001). But instead I get 0.0999999 recurring.
I have tried with Math.trunc as well but get the same results.
Would anyone know why this is?

Why the result is like this [duplicate]

This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 4 years ago.
var tm=110;
var fm=200;
var pr=Math.ceil(tm/fm*100);
console.log(pr);
The result is showing 56.
But it should be 55
Note that
tm/fm*100 is resulting 55.0000001
But
When tm=100 and all fm=200 then the result is 50
I've solved that problem concedering upto 2 decimal places after point, I could not understand where from 1 is comming after some 0s!
Math.ceil() returns the smallest integer greater than or equal to a given number. See MDN Documentation.
Remove Math.ceil()
parseFloat() pr variable
Call Float's precision method toPrecision(8)
The extra 1 you are seeing is a result of binary floating point math. JavaScript does this. Source
<script>
var tm=110;
var fm=200;
var pr= parseFloat(tm/fm*100);
alert(pr.toPrecision(8)); // output: 55.00000000
</script>

Simple Calculation - JavaScript [duplicate]

This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 8 years ago.
I am performing a basic calculation using javascript and when I use this combination of number it won't calculate correctly:
alert((40071.13 + 6028.91) - 46100.04);
It should calculate to 0 but it doesn't. All other number combinations work for me.
Help!
This is a rounding issue. Try this to round to 2 decimal places
var num = (40071.13 + 6028.91) - 46100.04;
alert(num.toFixed(2));
See it in action on jsFiddle

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