How can I call upon a randomly generated number to determine a symbol spawn?

so what I'm trying to do is generate a random number from 1 to 3 when a symbol on the stage is clicked. Once this number is generated, i want this number to determine which of these next 3 symbols will spawn. How can I call upon this function's random number? Does the random number the generator spits out need to be declared as an integer?

//Random hitmarker generator
function randomRange(minNum:1, maxNum:3):Number 
    return (Math.floor(Math.random() * (maxNum - minNum + 1)) + minNum);
}
if (Number = 1){
    boom.x = 340;
    boom.y = 600;
    boom.visible = true;
}
if (Number = 2){
    boom.x = 370;
    boom.y = 500;
    boom.visible = true;
}
if (Number = 3){
    boom.x = 330;
    boom.y = 340;
    boom.visible = true;
}