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


Share

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.

How did you use this starter? Can you suggest how teachers could present or develop this resource? Do you have any comments? It is always useful to receive feedback and helps make this free resource even more useful for Maths teachers anywhere in the world.
Click here to enter your comments.

If you don't have the time to provide feedback we'd really appreciate it if you could give this page a score! We are constantly improving and adding to these starters so it would be really helpful to know which ones are most useful. Simply click on a button below:

Excellent, I would like to see more like this
Good, achieved the results I required
Satisfactory
Didn't really capture the interest of the students
Not for me! I wouldn't use this type of activity.

This starter has scored a mean of 3.3 out of 5 based on 180 votes.


Previous Day | This starter is for 15 March | Next Day

 

Answers

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



Casio Classwiz Calculator

There is currently a lot of talk about this new calculator being the best in its price range for use in the Maths classroom. The new ClassWiz features a high-resolution display making it easier to view numerical formulas and symbols but it isn't a graphical calculator as such (it has the capacity to draw graphs on your smart phone or tablet, via a scannable QR code and an app).

As well as basic spreadsheet mode and an equation solving feature you also get the ability to solve quadratic, cubic or quartic polynomial inequalities and the answer is given just as it should be written down, using the correct inequality symbols!

This calculator has a high-performance processor and twice the memory of previous models ensuring speedy operation and superior computational power.more...

Online Maths Shop

Laptops In Lessons

Teacher, do your students have access to computers?
Do they have iPads or Laptops in Lessons?

Whether your students each have a TabletPC, a Surface or a Mac, this activity lends itself to eLearning (Engaged Learning).

Laptops In Lessons

Here a concise URL for a version of this page without the comments.

Transum.org/go/?Start=March15

Here is the URL which will take them to a related student activity.

Transum.org/go/?to=Bidmaze

Student Activity


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.

You can find more about the word ides in the comments of the Roman Numerals Starter.

Roman Numerals
Apple

©1997-2017 WWW.TRANSUM.ORG