Using the least number of mathematical symbols make this formula correct:
1 2 3 4 5 6 7 8 9 0 = 100


Answer: 1 2 3 4 5 6 7 8 9 0 ≠ 100
A slashed 'equals' sign is the mathematical symbol for 'does not equal'. If the above code does not display correctly it can alternatively be shown as: =/=

Other possible answers
1x(2+3)x4x5+(6x7x8x9x0) = 100
1(2+3)x4x5+(6x7x8x9x0) = 100
1x(2+3)x4x5+6x7x8x9x0 = 100
1+2+3+4+5+6+7+8x9+0 = 100
1x(2+3)x4x5+6789x0 = 100
1x2x3x4+5+6-7+8x9+0 = 100
123+45-67+8-9+0=100

paris in the spring
Quickly, what do the words in the underneath say?
paris
in the
the spring

Most people will say "Paris in the Spring".
People tend to make this error even without seeing the introductory heading.
This tendency demonstrates how we read: not by looking at each word separately, but by seeing and recognizing several words at a time, especially if the phrase is an understandable concept.
This unconscious quick processing by the brain is normally helpful because it saves time, but on occasions it can fool us.
The puzzle shows how vulnerable we are to false assumptions, and particularly that sometimes we lazily rely on our brain's ability to process information extremely quickly, when really we should be over-riding this unconscious processing by consciously focusing on the detail.
The exercise will work with phrases other than Paris in the Spring, provided you keep to the same pattern.


How many 'f's?
This puzzle has been fooling people for decades. You can use it to demonstrate how our mind sometimes plays tricks on what we believe. The puzzle can also be used to support themes of concentration, accuracy, assumptions, and creative or lateral thinking .
The layout is probably important in the way that it works. Show the box below to people and ask them to read the words and count the number of times the letter f (or F) appears. Most people get it wrong. Try it yourself, and then check your answer carefully. It's not a trick question - the trick is the way the mind works identifing the letters.

How many 'f's?
FINE POINT
It is easy to miss the finer
points in life. Folk are
frequently guilty of
falling into this trap.


The letter f appears eight times in the box. People commonly count seven, by failing to see the last but one f.
Did you?
And if you found that one too easy, try this one.
Again, how times does the letter f (or F) appear in the following item?

Finished files are the
result of years of scientific
study combined with the
experience of years.


Did you find all six?