# Writing a number in terms of other numbers.

• March 15th 2010, 04:42 PM
dmfnsdkjdj
Writing a number in terms of other numbers.
okay so im trying to figureout how i can get some numbers only using the numbers : 9,7,5,1 you can use any symbols like adding or substracting or square rooting etc but u gotta use each number only once and you gotta use all four of them. the numbers that i am trying to figure out are : 7,30,36,46,54,55,66,71,72,83,84,86,89,92-96,100 i would greatly appreciate if you could help me with this thanks.

for example:45=7x5+9+1
or 82= 9^(7-5)+1
• March 15th 2010, 07:31 PM
Soroban
Hello, dmfnsdkjdj!

I found a few of them . . .

. . $\begin{array}{ccc}
7 &=& 1\cdot(5+9-7) \\ \\
36 &=& \sqrt{9}\cdot(5+7) \div 1 \\ \\
55 &=& 5\cdot(1+7+\sqrt{9}) \\ \\
71 &=& (5-1)^{\sqrt{9}}+7 \end{array}$

. . $\begin{array}{ccc}
84 &=& 7\cdot\sqrt{9}\cdot(5-1) \\ \\
91 &=& 7\cdot(9+5-1) \\ \\
96 &=& (1+5)(7+9) \\ \\
100 &=& (1+9)^{(7-5)}
\end{array}$