Let's call our number as x. Since 660 is 12% of x, we know that
[tex]x\cdot\frac{12}{100}=660[/tex]Solving this equation for x, we have
[tex]\begin{gathered} x\cdot\frac{12}{100}=660 \\ x\cdot0.12=660 \\ x=\frac{660}{0.12}=5500 \end{gathered}[/tex]660 is 12% of 5500.
