Spark's math

Spark and I were going over some problems, he uses Singapore math, and he keeps getting tripped up on what to do because he doesn't look at the sign (+, -, x or division).  He is adding when he should be subtracting or he will multiply half a problem and add the other half, etc.  To try and put the importance of watching the signs in boy terms, I told him that math is just like driving.  He will need to read the road signs when he drives and he has to read the math signs when he does math.  On each problem I would draw an outline of a sign complete with grass growing around the bottom of the post.  We came to one and I said to him, "What is this sign?"  "Minus," he says.  I say it again louder, he says "minus" louder, and so on for three times to really make it sink in until we are almost yelling the question and answer like a cheer at a basketball game.  The last time I say "What is this sign?" and he says in a regular voice "subtraction."  Well, that really got us laughing and we needed to take a little break to recover.  The good news, he has been looking at those math signs ever since!