You have got only 10 seconds to solve it! Can you?


“Pure mathematics is, in its way, the poetry of logical ideas.” — Albert Einstein.

Frankly speaking, I have never been quite good at calculating. I’m not really hopeless at counting out the money. So, I can handle the sums in the shops. And of course, I can easily work on calculator. But I’m not so good when it is about multiplication and division in my head.

So, to be honest, when I had a first look at this mathematical riddle I felt a bit confused. But then I concentrated and did my best in 8 seconds!

Fortunately, for those who are not mathematically-minded there are some useful tips how to improve this situation.

If you want to get better at math or do it faster in your head, so you can do better at work or do better in school, there’s a way to do so.

One of the things my Dad taught me early on was to do math in my head, whenever I could. He taught me to round things to 10’s, 100’s, 1000’s, and to re-arrange the math and break it down if it was, too complex.

This helps, whether you’re doing math in your head, or doing some quick figures on paper, or even using a calculator.

If you can do quick math estimates in your head, it gives you an advantage at work when people are throwing numbers around. This can help you quickly get a sense of how many, how much, how often, or what percent, when people are throwing numbers you way.

It can also help you in interviews under pressure, or it can help you day-to-day to get a rough idea of how much you are spending at the store.

More importantly, if you can quickly get to ballpark estimate and make meaning out of numbers, you can focus on the bigger context, or play out “what if” scenarios, rather than get distracted, or lose the flow, while you pull out calculators or number crunch.

And, in a lot of scenarios, not everybody is going to wait for you to pull out a calculator, or catch up.

Ok my smart friend, let’s see if you did it right and if 10 seconds were enough…