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

Andrew Denson
Andrew Denson
4,544 Points
Posted by Andrew Denson
Andrew Denson
4,544 Points

Question on the Random Challenge code

var newNumber = Math.floor(Math.random() * (randomNumberTwo - randomNumberOne + 1)) + randomNumberOne;

My questions is why do you need the parenthesis around this (randomNumberTwo - randomNumberOne + 1)) for it to work properly. I know you need it for it to work, just looking for explanation on the purpose it serves.

Thanks

2 Answers

Jackson Monk
Jackson Monk
4,527 Points
Jackson Monk
Jackson Monk
4,527 Points

You are just using basic math order of operations, telling the interpreter that within the set of innermost parentheses is what you what to do first

Mike Hatch
Mike Hatch
14,940 Points
Mike Hatch
Mike Hatch
14,940 Points

The official way of describing it is called Operator precedence. Scroll down to the Table area. It will show you the order of precedence for multiplication, addition, subtraction, etc.

A simple example: 

let a = (1 + 2) * 3)      
a                            // 9 

// This is parsed from left to right because the parentheses take higher precedence.

If you instead typed:

let a = 1 + 2 * 3 
a                            // 7 

// This is parsed from right to left because multiplication takes higher precedence.