Brain teasers with 9 numbers

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Mathematical puzzles

Math problems
5 numbers for pupils

Brain teasers
Puzzles with 9 numbers

For parents
How to motivate kids

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Number puzzles as mental jogging from 10 years upwards

Brain teasers in various levels of difficulty ("easy", "medium", "hard" and "very hard") will keep your grey cells active. Nine single-digit numbers are linked using the basic arithmetical skills, setting you challenges in terms of mental arithmetic, concentration, logic and retention of data. A varying quantity of numbers in different patterns are provided in advance to help you, with the amount of help depending on the level of difficulty selected. And even for experienced math 'experts' and problem solvers there are some hard nuts to crack – you'll be surprised at the number of possible combinations there are. Ten minutes spent every day in mental jogging will make a noticeable difference to your intellectual fitness.

You enter a number from 1 to 9 in the squares, but numbers can only be used once. The rule about multiplication/division ahead of addition/subtraction doesn't apply!

Select difficulty level:
Easy number puzzles:
Easy mental jogging online
In the easy problems only 3 of the 9 numbers are missing. They can be done in your head without the need to make notes. They are also still suitable for primary/elementary school children. If required the quantity of numbers given in advance can be pre-selected (otherwise they change at random):

Medium number puzzles:
Medium mental jogging online
At the medium difficulty level 5 of the 9 numbers are provided. It's useful to have a sheet of paper for 'what if' calculations. These problems are already pretty difficult for children. 5 different patterns are available:

Hard number puzzles:
Hard mental jogging online
The difficult problems with only 4 numbers to help you are a real challenge, but perseverance and puzzle skills will get you there in the end:

Very hard number puzzles:
Very hard mental jogging online
As if the 'hard' level wasn't hard enough, the very hard ones only give you 3 numbers to work with. And if these puzzles, too, are not demanding enough for you, please contact us - doesn't want any genius out there to start feeling bored ;-)

In order to ensure that clear answers are always produced it is not advisable to modify the math problems, which were designed with a special software program.

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