-3,6:1,8

It seems like you've entered a pair of numbers with a colon, which may represent a ratio: -3.6:1.8. If you're looking to simplify this ratio or convert it into fraction form, here's how to do it:

1. Write the ratio as a fraction: \[ \frac{-3.6}{1.8} \]

2. Simplify the fraction: Divide both the numerator and the denominator by the greatest common divisor (GCD). Here, you can divide both by 1.8:

   \[ \frac{-3.6 \div 1.8}{1.8 \div 1.8} = \frac{-2}{1} = -2 \]

So the simplified form of the ratio -3.6:1.8 is -2:1.

If you need something else regarding these numbers, please provide more context!