Step-by-step Solution:

\[ \textbf{Solution:} \] \[ \text{Let the original number be } 100. \] \[ \text{After increasing by }30\%: \quad 100 + 30 = 130. \] \[ \text{Now decrease this by }20\%: \quad 130 - \frac{20}{100}\times 130 = 130 - 26 = 104. \] \[ \text{Final value} = 104. \] \[ \text{Net change} = 104 - 100 = +4. \] \[ \text{Net percentage change} = \frac{4}{100}\times 100\% = 4\%. \] \[ \therefore \ \boxed{\text{The net change is an increase of 4\%.}} \]