Welcome

At the 7puzzle company, we produce regular number puzzles for our many followers from nearly 100 countries throughout the world. Our aim is to help improve basic knowledge and confidence of number & arithmetic in a fun way.

Enjoy your visit and spread the message about the fabulous number puzzles at 7puzzleblog.com. Try our latest challenge, #61, which is one from an entrance test. There are also several hundred others at this website.

Click this link if you wish to find out more about our main school-based maths workshops, the 7puzzle experience.

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

Paul Godding, Director of the 7puzzle company

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#61

A palindromic number is a number that can be read the same forwards and backwards (e.g. 33 and 797). How many of such numbers are there between 10 and 1,000?

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#60

Find the values of eight letters, A to H, from the given information. Each letter contains a different whole number in the range 2-50. Good luck:

  1. C is an odd number lower than H,
  2. D is an even number,
  3. G minus F is either 11 or 12,
  4. a fifth of B is equal to a third of C,
  5. F minus D is an odd number,
  6. H is a third of F, and E is a third of B,
  7. G divided by five is a whole number and odd,
  8. D is equal to B minus C,
  9. A is equal to 150 minus the sum of the other seven numbers.

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#59

You have been given a starting number, 18, and must arrive at the same final answer. There are ten arithmetical steps from beginning to end, each involving a whole number. Unfortunately the 9th, and penultimate, step is missing! What should it be?

Start at 18, then:

÷2     +3     –8     ×6     +4     –3     ÷5     ×2     ?     ×2     =     18

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#58

Starting from 1, find the sum of the first SEVEN whole numbers that do not contain a 3, 5 or 7 as part of their number, or are not multiples of 3, 5 or 7.

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#57

Replace the 12 ?’s below with 1, 1, 2, 2, 3, 3, 4, 4, 5, 6, 7 and 8:

?  +  ?     =     5     =    ?  –  ?
?  +  ?    =      9     =    ?  ×  ?
?  +  ?    =      8     =    ?  ÷  ?

so that all three lines work out arithmetically. Enjoy!

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#56

Replace the 12 ?’s below with 0, 1, 2, 2, 3, 3, 4, 6, 6, 7, 9 and 9:

?  +  ?     =     6     =    ?  –  ?
?  +  ?    =     18    =    ?  ×  ?
?  +  ?    =      3     =    ?  ÷  ?

so that all three lines work out arithmetically. Good luck!

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#55

This is the 2nd and final part of ‘Can You Pass A Simple Math Test’ containing another five multiple choice questions. The other five are in Challenge #54. Can you achieve 5 out of 5?

1. How many seconds are in 2 hours?

A 8,300     B 7,200     C 3,600     D 9,000

2. Solve (4 × 5) + (7 18÷3).

A 42     B 74     C 23     D 21

3. What is 235 × 13?

A 3,125     B 3,055     C 3,575

4. If c + d = d, what must c equal?

A 1     B 0.5     C 0

5. Which decimal is equivalent to 3/5?

A 0.35     B 0.53     C 0.6     D 0.3

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#54

This is the 1st part of ‘Can You Pass A Simple Math Test’ containing five multiple choice questions. The other five are in Challenge #55. Can you get 5 out of 5 in this test?

1. Which fraction is greater than 2/3?

A 2/6     B 4/5     C 1/3     D 1/6

2. Susan’s pen is 13/100 of a metre long. What is the length, in metres, of Susan’s pen?

A 0.013     B 1.3     C 1.03     D 0.13

3. What is Pi rounded to 3 decimal places?

A 3.784     B 3.267     C 3.142     D 3.168

4. If 4y = 10÷5, what is the value of y?

A 0.5     B 4     C 2     D 1

5. Tom is 1/3 of Joe’s age. David is 1/2 of Joe’s age. Who is the youngest?

A Joe     B Tom     C David

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#53

From the numbers 2, 4, 5, 6, 8, 9, 10, 12, 14, 15, 18, 20, 24  and 25, eliminate the square numbers, triangular numbers, multiples of 4 and factors of 70. There should now be just one number left, what is it?

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