Welcome

At the 7puzzle company, we produce regular number puzzles for our many followers from 130 different countries and territories. Our aim is to help improve the basic knowledge and confidence of number & arithmetic in a fun way for people all over the world.

Enjoy your visit and spread the message about the fabulous number puzzles at 7puzzleblog.com. Try our latest challenges, #97 & #98, which will fully test your arithmetical and logical skills. There are over 1,000 number challenges to try at this website if you delve deep enough!

You can also follow me and my tweets at @7puzzle.

Paul Godding: Owner, the 7puzzle company

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#98

In the following sequence puzzle, there are 2 rules to consider when arriving at the next number:

  • if EVEN, halve it
  • if ODD, add 1

So, if starting at 50, the sequence would be 50, 25, 26, 13, 14, 7, 8, 4, 2, 1 . . . thus taking nine steps to get to 1.

Following the above rules, which starting number between 50 and 100 would give you the most steps (13 in all) when eventually arriving at 1?

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#97

By analysing the relationship between this series of consecutive numbers, what is the 7th number in the sequence, and why?

7    5    10    8    16    14    ?

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#96

You need to carry out some addition and subtraction, together with a bit of logical thinking, to answer this question:

F=A+B;   G=B+C;   H=C+D;   I=D+E;   J=F+G;   K=G+H;   L=H+I;   M=J+K;   N=K+L;   P=M+N.

If B=9, E=5, I=6, J=26 and L=13, what is the value of P?

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#95

Another number puzzle similar to my Mathelona app. Visit mathelona.com for details.

Can you replace the 12 ?’s below with 0, 1, 1, 2, 2, 3, 3, 4, 6, 6, 7 and 7:

?  +  ?    =     2     =    ?  –  ?
?  +  ?    =     9     =    ?  ×  ?
?  +  ?    =     7     =    ?  ÷  ?

so that all three lines work out arithmetically?

MathelonaLogo

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#94

This number puzzle is associated with my mental arithmetic and strategy board game, the possible game.  Further details can be found at mathematicallypossible.com.

Using the numbers 3, 5 and 5 once each, with + – × ÷ available, which four numbers from the following list are not mathematically possible to make?

1    4    7    10    13    15    18    20    22    25    28    30

MathelonaLogo

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#93

Your task is to arrive at the target answer of 18 by using each of the four numbers 2, 6, 7 and 10 exactly once each, with + – × ÷ available. Can you make 18?

MathelonaLogo

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#92

List seven different whole numbers that total 101, but:

  • each number must be at least 4 away from one another,
  • the list must contain THREE square numbers.

There are a few different solutions!

MathelonaLogo

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#91

In all four lines below, replace each ? with either + – × or ÷ below so the result is 38 every time. Work one step at a time, from Left to Right, and no brackets are allowed:

  •   7   ?   8   ?   9   ?   9   =   38
  •   2   ?   9   ?   3   ?   5   =   38
  •   6   ?   4   ?   9   ?   2   =   38
  •   8   ?   2   ?   8   ?   6   =   38

MathelonaLogo

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#90

Your task is to arrive at the target answer of 24. You must use each of the four numbers 0.5, 1, 5 and 10 exactly once each and have + – × ÷ available.

MathelonaLogo

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