The rules in one minute
Pick a level: addition, subtraction, multiplication, division, mixed sums or percentages. Every answer is a whole number of zero or more, so subtraction never goes negative and division always comes out exact.
Type with the on-screen keys or your keyboard. A correct answer is accepted as soon as it is complete; there is nothing to confirm. If you are stuck, press OK to give your answer anyway or to skip. That sum counts as wrong and you move on.
Every five correct answers the numbers grow a step. Addition starts with single digits and ends with three-digit numbers, so a strong minute gets harder as it goes.
Getting faster
- Add from the left. For 47 + 38 think 70, then 15, then 85. It is quicker than carrying in your head.
- Subtract by counting up. 92 − 57: from 57 to 60 is 3, to 92 is 32 more, so 35.
- For multiplication, learn the awkward pairs once: 6×7, 7×8, 6×8, 7×9. Most slow answers are one of them.
- Percentages are fractions in disguise: 25 % is a quarter, 20 % a fifth, 75 % three quarters.
- Skip early, not late. A sum you cannot see after two seconds is cheaper to skip than to fight.
A good first target is fifteen correct answers on addition. Twenty-two or more is a very quick minute.
Choosing a level
Each level trains something different. Addition and subtraction are about speed with carrying and borrowing. Multiplication starts with the small times tables and moves to larger factors as you score. Division is the same tables backwards and always comes out exact. Mixed sums switch between the four operations, so you have to read the sign every time. Percentages ask for simple shares of round numbers, such as 10 % of 70 or 75 % of 40.
The game keeps your best for each level separately and draws your last twenty minutes as a chart, so you can see a level getting easier week by week.
Questions
What happens if I type a wrong answer?
Nothing until you press OK. The game waits for a correct answer and only counts a sum as wrong when you submit or skip it.
Can the answer be negative or a fraction?
No. The sums are built so that every answer is a whole number of zero or more, including division and percentages.
How does Quick Sums work as the Spark lamp?
On Spark days the level follows the weekday: addition early in the week, subtraction midweek, mixed sums at the end. Fourteen correct answers give two rays and twenty-two give three (ten and seventeen on mixed sums). See today's strand.
Do I need a keyboard?
No. The on-screen keypad is made for thumbs, and the number keys of a keyboard work too.