a = 6 * 10²³
b = 5 * 10¹⁹
a * b = 6 * 10²³ * 5 * 10¹⁹ = 30 * 10⁴² = 3 * 10⁴³
a : b = 6 * 10²³ : 5 * 10¹⁹ = 1,2 * 10⁴
