Doubt!! Consider the number 89.
for "8" the initial value added is 0, as initial value is specified in reduce method.
So for "9" , the accumulator(8) will be added to 9.
Is 0 used as initial value for all indexes in array?

Great explanation PixelLemons! :)

I like the soloution with the extra + to convert it

very clear!

very clear!

The "i" means case-Insensitive

Create anonymous function with parameter named 'x' like function(x) { return ... }
Where ... is expression after '=>' =)

Same as:
howManySmaller =function(arr,n) {return arr.map(function(x){return x.toFixed(2)}).filter(function(x){return x<n} ).length}

after "n % 2" is evaluated and used in condition, n is decremented by 1 (n = n - 1).

"--" and "++" are decrement and increment operators.
"x--" means use first then decrement by 1, "++x" means increment by 1 first then use.