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

• 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.
•
• Really good. Got my brain thinking...
96/4=24
24-4=20
20-4=16
16/4=4
4/4=1
•
• 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.
• Ashwin, India
•
• Important tip:- you can the digit twice as well like 44 -).
• Sue, Australia
•
• I guess it's good for introducing algebra or even discussing multiples. It's a bit simple other than that - it's obvious any number can be reduced.
• Yannis Lee, King George V School, Hong Kong SAR
•
• 68÷4=17
17+4=21
21×4=84
84-4=80
80÷4=20
20÷4=5
5-4=1.

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.

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## Curriculum Reference

See the National Curriculum page for links to related online activities and resources.

## 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.

## Extension Activity

A coin bearing the year 44 BC was discovered last year using a metal detector, with the date still legible. How can one be absolutely certain that the coin is fake?

For Students:

For All: