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.

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.

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

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

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