function solve(number) {
    let arr = Array.from(String(number));
    let lastDigit = arr[arr.length - 1];
    switch (lastDigit) {
        case '0':
            console.log('zero');
            break;
        case '1':
            console.log('one');
            break;
        case '2':
            console.log('two');
            break;
        case '3':
            console.log('three');
            break;
        case '4':
            console.log('four');
            break;
        case '5':
            console.log('five');
            break;
        case '6':
            console.log('six');
            break;
        case '7':
            console.log('seven');
            break;
        case '8':
            console.log('eight');
            break;
        case '9':
            console.log('nine');
            break;
    }
}
solve(1643);