Flashing Digits Sum Game

About Sequence Sum

Sequence Sum flashes single digits in the middle of the screen, one after another, each for less than a second. When the last digit has gone, you type the sum of all digits. You have to remember only one number, the running total, as long as you add every digit when it appears.

There are 3 digits on level 1 and 8 on level 10. Each digit is visible for about 850 milliseconds on level 1 and 470 milliseconds on level 10, with a short pause between digits. An exact total scores 100, and a close total still earns up to 85 points.

How to play

1. Watch the digit and add it to your running total. For 4, 7, 2, say 'four, eleven, thirteen'.
2. Do not try to remember all digits; remembering only the total is easier.
3. When the last digit is gone, type the total and press Lock in or Enter.
4. The result note shows the complete sum, like 4 + 7 + 2 = 13.

Single digits flash up one after another. Add them up as you go and type the total at the end. Close answers still earn points.

How scoring works

An exact total scores 100. A wrong total is scored by its distance from the right one: it can earn up to 85 points, and the score reaches 0 at 20 percent of the total, with a minimum of 3. For a total of 30, being off by 2 earns about 67 points.

The digits are between 1 and 9 and are drawn at random. The number of digits is 3 on level 1 and 8 on level 10. Each digit is shown for 850 ms on level 1 and 470 ms on level 10, followed by a pause of 260 ms and 160 ms. You have 10 seconds to answer.

What it trains

The game trains working memory updating and mental addition at the same time. It is the skill of keeping a running total, as when you add up prices while shopping or keep score in a game.

It also shows how much easier a task becomes when you pick a good strategy. People who try to remember all digits usually do worse than people who update a single number.

Tips for a higher score

• Update a running total after each digit. Say the new total silently, not the digit.
• Use pairs that make ten. If you see a 7 and then a 3, you can think 'ten' in one step.
• Do not look back. Once a digit is gone, concentrate on the next one.
• If you lose a digit, keep adding the following ones and make a rough guess at the missing one. A close answer still earns points.
• Practise at low speeds first. On level 10 you must add within half a second.

The idea behind it

Keeping a total in mind and updating it is a classic working memory updating task. The work of Akira Miyake and colleagues in 2000 identified updating, shifting and inhibition as three distinct functions of executive control, and tasks like the running sum are standard measures of the first.

Digit span, the number of digits you can repeat back, has been used in intelligence testing since the late nineteenth century and is about seven for most adults, but a running total only requires remembering a single number at any time. That is why the strategy of adding as you go makes the game feasible even with eight digits.

Related games

Free, no account. Your best scores are saved on your device.