Only One Number: Reduce 68 to one using only the 4 key and any operations.





Correct. You Did It!

68 can be reduced to 1 by using only the number four key and any of the operation keys.

For example:

68 - 4 = 64
64 ÷ 4 = 16
16 ÷ 4 = 4
 4 ÷ 4 = 1


How many other numbers can be reduced to 1 using only the four key and any of the operation keys?

Starting number:      Calculator button:

A Mathematics Lesson Starter Of The Day


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Topics: Starter | Arithmetic | Calculator | Investigations | Number

  • Sue Sunn, St Albans
  •  
  • 76 +4 = 80
    80/ 4 = 20
    20 / 4 = 5
    5 - 4 = 1
  • Francisco Schreiber, Rokeby School East London
  •  
  • Divided by 2 is a good starting point for foundation groups.
  • Miss Sidebotham, -
  •  
  • This starter was a good one, the children loved it.
  • Zara, Belmont Academy
  •  
  • Really good. Got my brain thinking...
    How about... 96
    96/4=24
    24-4=20
    20-4=16
    16/4=4
    4/4=1
  • Jordan, Admirals Junior School
  •  
  • Sixty eight plus four plus four plus four plus four plus four plus four plus four plus four divided by four take away four take away four take away four take away four equals ONE!
  • Teacher, UK
  •  
  • Actually any number can be done this way,
    Take the number a
    do a x 4 = 4a
    -4
    -4
    -4... (a-1) times
    so were left with 4
    then divide by 4
    I think it's a reasonable starter so I rated it 2 but it needs a limit to the number of operations allowed.

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Answers

It is possible to reduce any number to one using any calculator key.



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And now for something completely different.

The 15th March is referred to as the 'ides of March' in a Shakespeare play. The date was notorious as the date of the assassination of Julius Caesar in 44 BC. The death of Caesar made the Ides of March a turning point in Roman history.

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