Number Memory,
hold the number in mind.

Why digits are hard to hold

Number Memory is a forward digit-span task. You see a number, it hides, and you give it back in the same order. Psychologists have used tests of this kind for more than a century, because they show how much your short-term memory holds before details start to slip.

The well-known limit is a handful of items, not a handful of digits. That difference is the whole strategy. If each digit counts as one item, you run out of room quickly. If you can pack two or three digits into one item, the same memory holds far more. That packing is called chunking, and nearly every long run in this game uses it.

Chunking in practice

The digits appear as a plain row of single tiles with no spacing, so the grouping has to come from you.

• Use groups of three. Read 572049318 as 572, 049, 318. Groups of three are easy to say and easy to count.
• Say each group as a number. "Five seventy-two" is one sound. "Five, seven, two" is three.
• Keep the sizes steady. Mixing twos and fours in one number makes you lose track of where each group ends. When the length doesn't divide by three, put the odd group at the end: 10 digits as three, three, two, two.
• Grab the meaning when it's there. A year, a run like 345, a double like 88, or a number you know well is one easy chunk.

A worked example

At nine digits the number stays on screen for just over seven seconds. Say it shows 572049318.

1. Split it as you read: 572, 049, 318.
2. Say it in rhythm: "five seventy-two, oh forty-nine, three eighteen".
3. Say it a second time without reading. Then check it against the screen.
4. If both match, tap "I'm ready". If one group was shaky, use the remaining time on that group alone.

Then type at once, one chunk at a time, saying the rhythm to yourself. There is no time limit on typing, but the memory fades if you wait.

Before you press Enter, check your answer. You can delete digits until you submit. Read your typed number back in the same groups and compare it with the rhythm you are holding. Slips in the middle of a long number are easy to miss, and this check catches them.

Mistakes that end runs early

• Reading digit by digit. If you notice yourself naming single digits, stop and regroup.
• Hiding the number too soon. "I'm ready" is for when you have said the number once from memory and checked it. Hitting it the moment you finish reading saves a few seconds and costs runs.
• Rehearsing silently with no rhythm. A steady spoken pattern in your head holds better than a picture of the digits.
• Losing count. Each level adds exactly one digit. Know how many your answer should have. If your groups add up to the wrong length, a group is missing a digit.
• Typing extra digits. An answer longer than the number counts as wrong, just like a shorter one.

Pushing your best

The display time grows with length: a base beat plus extra time per digit, up to a cap of twelve seconds. So longer numbers do get more time, but each digit gets a little less of it, and past the cap much less. That is why a consistent chunking habit matters more as the run goes on. Practise it on the short opening levels, where it feels unnecessary. By ten or eleven digits it needs to be automatic.

Every number is random, and the first digit is never zero, so you can't learn the answers. You can only train the method. If you want the same skill with colours and a growing order, Color Sequence at /games/color-sequence adds one step per round instead of one digit.