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JavaScript JavaScript Basics (Retired) Working With Numbers The Random Challenge Solution

Samuel Trejo
Samuel Trejo
4,563 Points

Is it important when you use Math.floor()

e.g. Math.floor(Math.random * (max - min + 1)) + min VS Math.floor(Math.random * (max - min + 1) + min)

In the video he used Math.floor before adding the min number. Would there be any problems using it after adding the min?

1 Answer


You could do it all together ensuring you follow the order of mathematical calculation. But it also depends on the result you are wanting as the Math.floor() function returns the largest integer less than or equal to a given number, so that might affect your maths.

You may need brackets around the first maths operators on more complex maths:

Where this could go wrong... let's assume min is 1.5 and max is 10.

Let's also assume that the random number was 10 for both of them for the simple sake

var min = 1.5;
var max = 10;

// Math.random is 10 in this example for both
 Math.floor((Math.random() * (max - min + 1)) + min); // returns 96

 Math.floor(Math.random() * (max - min + 1)) + min ; // returns 96.5

In the first example, the Math.floor function returns the largest integer less than or equal to the whole maths calculation, which is 10 multiplied by (10 - 1.5 + 1) is 95 + 1.5 is 96.5, return the integer(whole number) of that which is 96.

In the second example Math.floor function does the same but not the last calculation so, 10 multiplied by (10 - 1.5 + 1) is 95 and then after that returns the integer of 95 its adds 1.5 to the end, returning 96.5