# Power digit sum help

How can i convert exponential to number ?

``````
function powerDigitSum(exponent) {
let num = Math.pow(2,exponent);
let arr = num.toString().split('');
return arr.map(numm => Number(numm)).reduce((number, total) => number+total, 0);

}

powerDigitSum(15);

``````

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Challenge: Problem 16: Power digit sum

What do you mean exponential to number?

Try this,

`````` let num = BigInt(Math.pow(2, exponent)
let arr = num.toString().split('');
//Now use .slice() to delete n from the Array
arr.slice(arr.length - 1)
// Mapping is not necessary
return arr.reduce((number, total) => number+total,);
``````

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