The 9s Trick That Actually Sticks (and the One I Tell Kids to Skip)

Why the 9s are the ones kids get stuck on

By the time a kid gets to the 9s, they've usually got the easy tables down. The 2s, the 5s, the 10s, all clean patterns. Then the 9s show up and everything slows down. I've watched a whole class fly through their times tables and then hit a wall at 9 times 6, 9 times 7, 9 times 8, counting on fingers under the desk and hoping I don't notice.

The good news is that the 9s have the best patterns of any table, which is why there are so many tricks floating around for them. The bad news is that most of those tricks are junk. They give a kid the answer without teaching them anything, and worse, some of them become a crutch that a kid drags around for years. So here's the 9 times table trick I actually teach, and the famous one I tell kids to leave alone.

The trick that sticks: the digits add to nine

Here's the pattern. In every answer to the 9s, up through 9 times 10, the two digits add up to nine.

• 9 times 2 is 18. One plus eight is nine.
• 9 times 3 is 27. Two plus seven is nine.
• 9 times 4 is 36. Three plus six is nine.
• 9 times 7 is 63. Six plus three is nine.

Every single one. And there's a second half that locks it in. The first digit of the answer is always one less than the number you're multiplying by. Take 9 times 7. One less than 7 is 6, so the answer starts with 6. The two digits have to add to nine, so the second digit is 3. Sixty-three. Done.

Why do I like this one? Because it's not really a trick. It's the actual structure of the 9s, and once a kid sees it, they can rebuild any 9s fact in a second or two even when they blank. It works on paper, in their head, on a test, forever. And it quietly teaches something true about how numbers behave, which pays off later in ways a gimmick never does.

Practice it like this. Say a 9s fact, and have your kid tell you the two rules out loud: first digit is one less, digits add to nine. Do it at dinner, in the car, five facts at a time. It sticks fast because the kid is doing the reasoning, not just memorizing a magic move.

The one I tell kids to skip: the finger trick

You've probably seen it. Hold up both hands, ten fingers. To do 9 times 4, bend down the fourth finger from the left. Fingers to the left of the bent one are the tens (three of them), fingers to the right are the ones (six of them). Thirty-six. It works, every time, and kids think it's magic.

Here's why I tell them to skip it, or at least to not rely on it.

It teaches nothing. The finger trick is a lookup table made of hands. The kid gets the right answer and learns exactly zero about why 9 times 4 is 36. There's no understanding underneath it, just a physical routine.

It doesn't transfer. The digit-sum trick works for 9 times 9 and, with a small stretch, points toward 9 times 12. The finger trick tops out at 9 times 10, because you run out of fingers. And it does nothing for any other table. A kid who leans on it has one narrow tool.

Worst of all, it becomes a crutch. I've had fifth graders quietly counting fingers under the table during a test because the finger trick was the only way they ever "knew" the 9s. They never actually learned the facts. They just learned the hand routine and stopped there, and now the 9s slow down every bigger problem they're inside of. Long division with a 9 in it turns into a finger ceremony.

The whole point of the times tables is fluency, being able to pull the fact instantly so your brain is free to work on the harder thing. A trick that keeps a kid dependent on their hands is working against that. It feels like progress because the answer is right, but it's the kind of shortcut that stalls a kid instead of moving them forward.

How to use tricks without getting trapped by them

A good trick is a bridge, not a home. It should help a kid over the hump while the facts become automatic, and then they should be able to walk away from it. The digit-sum trick does that. Kids use it for a few weeks, and then one day they just know that 9 times 7 is 63 and don't need the rule anymore. The finger trick doesn't let go. Kids are still doing it years later.

So here's my rule of thumb for any multiplication trick, not just the 9s. Ask whether it's teaching the pattern or hiding it. If the trick shows the kid something true about the numbers, keep it. If it just hands over the answer through some unrelated ritual, it's a crutch, and the kid will lean on it long after they should have let go.

The real goal isn't a kid who can perform the finger trick. It's a kid who hears "nine times seven" and says "sixty-three" before they've thought about it. Get them there with the pattern that makes sense, and the 9s stop being the wall in the middle of the times tables. They turn into the easy ones.