Method: $n_1$$u_1$ = $n_2$$u_2$, using dimensional formula [$M^a$ $L^b$ $T^c$]: $n_2$ = $n_1$ * $\frac{M_1}{M_2}$^a * $\frac{L_1}{L_2}$^b * $\frac{T_1}{T_2}$^c

Example 1: 1 Joule to CGS (erg) [E] = [ML^{2T}^{-2}] $n_2$ = 1 * (1000)^1 * (100)^2 * (1)^{-2} = 10^3 * 10^4 = 10^7 1 J = 10^7 erg

Example 2: G = 6.67 x 10^{-11} to CGS [G] = [M^{-1}$$L^{3T}^{-2}] $n_2$ = 6.67$x10^{-11}$ * (10^3)^{-1} * (10^2)^3 * (1)^{-2} = 6.67$x10^{-11}$ * 10^{-3} * 10^6 = 6.67 x 10^{-8} G = 6.67 x 10^{-8} dyne*$cm^2$/$g^2$

Key: Identify the dimensional formula first, then substitute the conversion factors for each base unit.