How to round an integer up or down to the nearest 10 using Javascript
JavascriptJavascript Problem Overview
Using Javascript, I would like to round a number passed by a user to the nearest 10. For example, if 7 is passed I should return 10, if 33 is passed I should return 30.
Javascript Solutions
Solution 1 - Javascript
Divide the number by 10, round the result and multiply it with 10 again, for example:
33 / 10 = 3.33.3 rounded = 33 × 10 = 30
console.log(Math.round(prompt('Enter a number', 33) / 10) * 10);
Solution 2 - Javascript
Math.round(x / 10) * 10
Solution 3 - Javascript
Where i is an int.
To round down to the nearest multiple of 10 i.e.
> 11 becomes 10
> 19 becomes 10
> 21 becomes 20
parseInt(i / 10, 10) * 10;
To round up to the nearest multiple of 10 i.e.
> 11 becomes 20
> 19 becomes 20
> 21 becomes 30
parseInt(i / 10, 10) + 1 * 10;
Solution 4 - Javascript
I needed something similar, so I wrote a function. I used the function for decimal rounding here, and since I also use it for integer rounding, I will set it as the answer here too. In this case, just pass in the number you want to round and then 10, the number you want to round to.
function roundToNearest(numToRound, numToRoundTo) {
return Math.round(numToRound / numToRoundTo) * numToRoundTo;
}