Edit in JSFiddle

var log = function(content){
    $('<p/>').html(content).appendTo('#log');
}

function doTask1(){
    var rslt = Math.floor(Math.random() * 10);
    log("Task 1 returned " + rslt);
    return rslt;
}
    
function addTask(i){
    var rslt = Math.floor(Math.random() * 10);
    log("addTask finished with " + rslt);
    return i + rslt;
}
    
function multiplyTask(i){
    var rslt = Math.floor(Math.random() * 10);
    log("multiplyTask finished with " + rslt);
    return i * rslt;
}
    
$(function(){
    var task1 = doTask1();
    var finish;
    if(task1 >= 5)
        finish = addTask(task1);
    else
        finish = multiplyTask(task1);

    log("All tasks finished with " + finish);
});

<div id="log"></id>