Why is the sum wrong? what i do not see in this?

let a = '254';

let b = 0;

for ( let i=0 ; i< a.length-1 ; i++ ) {
  b += a[i];

b results to ‘025’ not 11, why ?
this is don in the chrome dev tools.

Two issues. One is that your upper limit in the for-loop is wrong and not taking the last index from a.
Second is, that a is a string and JS decided to turn 0 from b into a string and thus adds the other characters from a to it. You want to cast the characters to integers so JS knows to add numbers there.

the first issue was a common mistake i do sometimes, but the second issue’s explination is helpful thank you.