Exc. 4

function compare(input) {
    let a = Number(input.shift());
    let endNum = Number(input.shift());
    let output = '';

    for (let startNum = a; startNum <= endNum; startNum++) {

        let numToString = String(startNum);

        let sumStartNums = 0;
        let sumEndnums = 0;

        let num1 = Number(numToString[0]);
        let num2 = Number(numToString[1]);
        let num3 = Number(numToString[2]);
        let num4 = Number(numToString[3]);
        let num5 = Number(numToString[4]);
        let num6 = Number(numToString[5]);

        sumOddNums = num1 + num3 + num5;
        sumEvenNums = num2 + num4 + num6;

        if (sumOddNums === sumEvenNums) {
            output += `${num1}${num2}${num3}${num4}${num5}${num6} `;
        }

    }

    console.log(output)

}