three 9's

[jonvantuyl]

how many intergers can be written with three 9's?

examples:

4480 = 9! / (9x9)
720 = 9*(square root of 9) - 9



this is an extra credit question for my math class. help please. thank you

[snakeeyes1000]

you don't tell us enough. Are the functions tan, cos, sin, etc allowed? What operators are allowed? How many parentheses? It sounds like this is a tedious assignment friend. If she is including everything, the possibilities are mind boggling. I would suggest studying for the next test rather than trying this.

[NotLKH]

There is another past thread similar to this.
Let me see if I can dig it up,

Plisken, What are you talking about?

[Bob Baddeley]

9 + 9 + 9=27
9 + 9 - 9=9
9 - 9 + 9=9
9 - 9 - 9=nope
9 + 9 / 9=10 or 2
9 + 9 * 9=162 or 90
9 - 9 / 9=0 or 8
9 - 9 * 9=0 or nope
9 / 9 + 9=10
9 * 9 + 9=90 or 162
9 / 9 - 9=undefined or nope
9 * 9 - 9=72 or 0
9 / 9 / 9=nope
9 / 9 * 9=9 or nope
9 * 9 / 9=9
9 * 9 * 9=729

then you have all the permutations with ^ ! ln log sqrt (which shouldn't be legal since it's ^(1/2), and a variety of other math functions.

[A$$Bandit]

9! shouldn't be allowed either (9 x 8 x 7 x ... )...