BrainBashers Daily 30 Seconds
Rate itStart from one number and follow a chain of sums in your head, in 30 seconds.
on brainbashers.com

Daily 30 Seconds is BrainBashers' mental arithmetic challenge. Each day there are new chains at three levels: press start, see a number, then double it, square it, take fractions or percentages of it, one step at a time, and give the result at the end.
About BrainBashers Daily 30 Seconds
BrainBashers, Kevin Stone's long-running puzzle site, runs Daily 30 Seconds alongside its daily brain teaser and logic grids. It is a test of mental arithmetic in short bursts.
You press start to see the opening number, then a series of instructions appears one at a time: multiply by two, times by itself, find three fifths, find 10 percent, take the square root and so on. You keep the running total in your head and give the final number at the end. The site admits not everyone can finish every chain within 30 seconds; the name is the target, not a hard limit.
There are easy, medium and hard chains, and a date picker lets you go back about four weeks to earlier days. Everything changes at midnight GMT. It suits anyone who wants a minute of mental maths a day, and parents looking for practice with children.
How to play BrainBashers Daily 30 Seconds
- Open Daily 30 Seconds and choose a difficulty: easy, medium or hard.
- Press start to see the starting number.
- Apply each instruction as it appears, keeping the running total in your head.
- Give the final number when the chain ends and check it.
- Try the other levels, or pick an earlier date from the list.
Tips
- Learn the shortcuts on the page: three fifths is a fifth times three, and two and a third is double plus a third.
- Say the running total under your breath after each step; it is easier to hold than to picture.
- Start on easy to learn the kinds of steps before trying hard.
Questions
Do I have to finish in 30 seconds?
No. It is the target. The site says not everyone can solve every chain within 30 seconds.
When do new puzzles appear?
At midnight GMT, along with the rest of BrainBashers' daily items.
Can I play earlier days?
Yes. A date list on the page goes back about four weeks.
What kinds of steps are there?
Doubling, squaring, cubing, fractions such as three fifths, percentages and square roots.
Ratings and reviews
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