Originally Posted by

**Euclid Alexandria** After a week I thought I'd give this another try. I'm using Soroban's formula to reproduce the mathematical joke,

$\displaystyle \frac{1\!\!\!\not{6}}{\not{6}4} = \frac{1}{4}$

While incorrectly solved, it still gives the correct answer. Any hints are appreciated on where I'm going wrong.

**Soroban's formula:**

We want digits $\displaystyle a, b, c$ so that: $\displaystyle \frac{10a + b}{10b + c} \:= \:\frac{a}{c}$

Solve for $\displaystyle c:\;\;c\:=\:\frac{10ab}{9a + b}$

**Step 1**

$\displaystyle \frac{10a + b}{10b + c} = \frac{a}{c} = \frac{a}{c}$