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6,609 Points# var num = Math.floor(Math.random() * upper) + 1; What exactly does 'upper' do? Dave added it some videos back

function getRandomNumber( upper ) { var num = Math.floor(Math.random() * upper) + 1; } Here's more

## 3 Answers

###### Jerry Hoover

**Full Stack JavaScript**Techdegree Graduate 25,815 Points

Upper is the name of the variable that represents the highest number that this function will produce. If upper=4, then this will return a random number between 0 and 4. If upper is set to 216 then it will produce a random number between zero and 216.

It does this by multiplying the result of math.random (a number between 0 and 1) by the value of upper, resulting in a float between 0 and the value of upper. Math.floor then rounds the value down to the nearest integer such that, if the result is 41.1657843, the stored value in ‘num’ will be 41.

###### Nayonna Purnell

**Full Stack JavaScript**Techdegree Student 6,683 Points

var num = Math.floor(Math.random() * upper) + 1; upper signifies the top number in the range of random numbers. Example: if we wanted a random number from 1 -6. Six signifies the upper number.

Math.random() gives us a number from 0 to 1. Math.floor- rounds the number down. In this particular example, Math.floor(Math.random() * upper) would give us a number from 1-5. The +1 would give us 6.

###### tp29

6,609 PointsThank you both. In other words upper is just a place holder