Make 21

1. Jan 17, 2005

vikasj007

Make the number 21 using the numbers:
1, 5, 6, 7

you can use:

I promise you it is straight forward maths and NO tricks... you can only use each number once and you cant use say 15 (the 1 and the 5 together) and you cant do like 5^6 or anything.

2. Jan 17, 2005

Rogerio

1*.5*6*7 ?

3. Jan 19, 2005

joshm

No TRICKS.

$$\frac{6}{1-\frac{5}{7}}$$

4. Jan 19, 2005

Galileo

Nice

5. Jan 19, 2005

mattmns

wow I was way off, I was not thinking about anything like that at all. good job.

6. Jan 20, 2005

vikasj007

good work joshm, especially for your first post.