Distance between earth and moon and and express in standard form

Solution;
The distance between earth and moon = 384400 km
the standard form of any number = K x 10ⁿ form , where  0< K < 10 and  n = any integer
So,$$\begin{gathered} 384400=3844\times 100 = 3844 \times {10}^2 \\ =3844 \times {10}^2 \times \frac{1000}{1000} \\ (multiply and divide by 1000 to place decimal after 3 place, So that 0<3.844<10) \\ =3.844 \times {10}^2 \times {10}^3 \\ =3.844 \times {10}^5 (x^a\times x^b=x^{a+b}) \\ So, the dis\tan ce between earth and moon =3.844\times {10}^{5}km \end{gathered}$$