hi
2 * 10³ + 8 * 10² = 2000 + 800 = 2800 = 28 * 10² 1/2500 = 4/10000 = 4 * 10⁻⁴
= root (28 * 10²)/(4 * 10⁻⁴ + 3 * 10⁻⁴) = root (28 * 10²)/(7 * 10⁻⁴) = root (4 * 10⁶) = 2 * 10³ = 2000
