Digital Century

[Greg Ward]

Place three common mathematical symbols between the digits:

1 2 3 4 5 6 7 8 9

So that the result equals 100
The same symbol can be repeated, but each repeat counts as one the three symbols you must use.
Rearranging the digits is not permitted.

Greg

[Scott]

1x(2+3)x4x5+6789 = 100

[Greg Ward]

Perhaps not.....
Now try it using only 3 symbols (same symbol can be used more than once)


Greg

[ajw]

123-45-67+89 = 100

ajw

[Scott]

1x2x3x4+5+6-7+8x9

I wonder how many permutations?

[Greg Ward]

That was great!
Now try this one:


Place a standard mathematical symbol between 4 & 5 to get a number greater than 4 and less than 5.

[ajw]

There would be dozens of possible solutions if you don't limit yourself to 3 mathematical symbols. Even more solutions if you could use parentheses to force an order of calculation.

ajw

[Scott]

4 + 5 ≠ 4.5

What do I win?

[Scott]

Actually, still thinking about that one. Let me put one back at you.

Place a standard mathematical symbol between 4 and 5 to get a number greater than 1000.

[ajw]

Place a standard mathematical symbol between 4 and 5 to get a number greater than 1000.

Too easy. 4^5=1024


ajw

[Greg Ward]

You win the profit from my sale of 2 bicycles.

I sold one for $300 a loss of 25%
and another for a gain of 25%.

How much do you get?

Greg

[ajw]

That was great!
Now try this one:


Place a standard mathematical symbol between 4 & 5 to get a number greater than 4 and less than 5.

One answer is 4+log(5). Is that the solution you had?

ajw

[Greg Ward]

This one really is just a trick.
Place a decimal point between 4 & 5 and you get....... 4.5

A policemen has forgotten his log book and he spots 3 speeding cars. He has a good memory and notes their 4 digit number plates easily as they all contain the same 4 consecutive numbers:
one, the correct order, one the reverse and the other higgledy-piggledy.
He also notices the three numbers added together total 12,300.

What are the number plates?

Greg

[ajw]

This one really is just a trick.
Place a decimal point between 4 & 5 and you get....... 4.5

A policemen has forgotten his log book and he spots 3 speeding cars. He has a good memory and notes their 4 digit number plates easily as they all contain the same 4 consecutive numbers:
one, the correct order, one the reverse and the other higgledy-piggledy.
He also notices the three numbers added together total 12,300.

What are the number plates?

Greg

2345, 5432, and 4523

ajw

[Scott]

Oooh, hats off

4 + 5 ≠ 4.5. Technically I was correct?