# Number of letters in the counting JavaScript

We are required to write a JavaScript function that takes in a number, say n. The function should count the letters in the number names from 1 to n.

For example − If n = 5;

Then the numbers are one, two, three, four, five.And the total number of letters are 19, so the output should be 19.

## Example

const sumUpto = (num = 1) => {
let sum = 0;
const lenHundred = 7;
const lenThousand = 8;
const lenPlaceOnes = [0,3,3,5,4,4,3,5,5,4];
const lenPlaceTens = [0,3,6,6,5,5,5,7,6,6];
for (let i = 1; i <= num; i++) {
let placeOnes = i % 10;
let placeTens = Math.floor(i / 10) % 10;
let placeHundreds = Math.floor(i / 100) % 10;
let placeThousands = Math.floor(i / 1000) % 10;
sum += lenPlaceOnes[placeOnes];
sum += lenPlaceTens[placeTens];
if (placeHundreds != 0) {
sum += lenHundred + lenPlaceOnes[placeHundreds];
}
if (placeThousands != 0) {
sum += lenThousand + lenPlaceOnes[placeThousands];
}
if (placeTens === 1) {
switch (placeOnes) {
case 4:
case 6:
case 7:
case 9:
sum += 1;
break;
}
}
if (i > 100 && i % 100 != 0) {
sum += 3;
}
}
return sum;
}
console.log(sumUpto(12));
console.log(sumUpto(5));
console.log(sumUpto(122));

## Output

This will produce the following output −

51
19
1280