Simple Calculation - JavaScript [duplicate] - javascript

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

Related

Extend to display decimal point number for more numbers [duplicate]

This question already has answers here:
JavaScript displaying a float to 2 decimal places
(14 answers)
Closed 3 years ago.
I am trying to display some decimal points.
Here are some examples.
console.log(1/100); // 0.01;
console.log(1/1000000); // 0.000001;
console.log(1/10000000); // le-7; but I want to see 0.0000001;
console.log(1/100000000); // le-8; but I want to see 0.00000001;
How to show decimal point numbers with keeping format?
You can use .toFixed(n):
console.log((1/10000000).toFixed(10))

Math.floor why is this rounding down incorrectly? [duplicate]

This question already has answers here:
Correcting floating math broken by multiplying, is it ok?
(1 answer)
Is floating point math broken?
(31 answers)
Closed 4 years ago.
I have been using this for sometime now before I noticed that is not reliable
Math.floor(16.65*100) / 100 = 16.64
Why does this happen? Any reliable alternative for rounding down safely in JS?
It's because 16.65 * 100 is calculated to 1664.9999999999998

Javascript plus equals 0.5 adding 0.50000000001 [duplicate]

This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 4 years ago.
I'm adding 0.5 to a number every second. However, it seems to be adding 0.5000000000001 instead.
window.setInterval(function() {
number += 0.5;
// it says number as 0.50000000001, and after 1.00000000002
}, 1000);
Does anybody know why this is happening?
It is a limitation of floating point numbers. They are not that accurate and hence the values that you have obtained.

Javascript - simple division leads to error [duplicate]

This question already has answers here:
How to deal with big numbers in javascript [duplicate]
(3 answers)
Closed 8 years ago.
If I use the windows calculator to calculate
(1.75 + 3/1.75)/2 it yields to =
1,7321428571428571428571428571429
If I do the same with javascript it yields to
1.732142857142857206298458550009
So at position 22 after the decimal point the result becomes incorrect ...142857... vs. ...206298...
var a = 1.75;
var res = (a+3/a)/2;
console.log(res.toFixed(30));
How can I make my division precise for 31 digits after the decimal comma?
Javascript can't do that "per se", since its double variables have a limited precision. You'll need to use an external library to handle operations with big precision numbers, like this one: Javascript Bignum

Rounding problems with calculate numbers in Javascript [duplicate]

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

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