What Happens to Unit If We Divide Two Resistance
The equation for two resistors in parallel is $$R_{\text{eq}} = \frac{R_1 \times R_2}{R_1 + R_2}$$

The numerator is a product of resistances so its unit is Ohms squared (\$\Omega^2\$).

The denominator is a sum of resistances so its unit is Ohms (\$\Omega\$).

Dividing the numerator by the denominator gives you Ohms: $$\frac{[\Omega^2]}{[\Omega]} = [\Omega]$$