simple Javascript loop does not work as expected

 let nmb = 0;
 for(let i=0; i<50; i+=2){
     nmb+=2;
     document.write(nmb + " ");
 }

This should solve the problem. The thing is, in your current solution, you are adding i number to the sum. So you add i=2 to nmb, nmb = 2. Then you add i=4 to nmb, nmb = 6, then you add i=6, nmb = 12 etc... You want to add constant value which is 2, not i value.

Your loop is already incrementing i by 2 which is the number you want to display, making the nmb variable unnecessary. So just write out i:

for(let i=0; i<50; i+=2){
    document.write(i + " ");
}

You are always adding i instead of 2 to your sum.

You could just print i directly

 for(let i=0; i<50; i+=2){
    document.write(i + " ");
 }

I wanted to do something with Array.from, but this was the closest I got

let x = [], r = 25, i = 0;
while (x.push(i += 2) < r);
console.log(x.join(","))