Mathematical calculation requires that the process be clear （1+1×3/1)×(1+2×4/1)×(1+3×5/1)×(1+4×6/1)… X (1 + 97 × 99 / 1) × (1 + 98 × 100 / 1) = how much

Mathematical calculation requires that the process be clear （1+1×3/1)×(1+2×4/1)×(1+3×5/1)×(1+4×6/1)… X (1 + 97 × 99 / 1) × (1 + 98 × 100 / 1) = how much

An = 1 + 1 / [n * (n + 2)] = [n (n + 2) + 1] / [n (n + 2)] = (n + 1) ^ 2 / [n (n + 2)] n = 1,2,3. A1 = 2 ^ 2 / (1 * 3) A2 = 3 ^ 2 / (2 * 4) A3 = 4 ^ 2 / (3 * 5) A4 = 5 ^ 2 / (4 * 6). A98 = 99 ^ 2 / (98 * 100) Note: A1 * A2 * A3 * A4 = 2 * 5 / 6, the square of 3 of A2 can be reduced from the denominator of A1 and A3

Required to write the necessary calculation process
For a certain type of diesel, it costs 4.2 yuan per liter. My uncle only has a steelyard instead of a measuring tool to measure the volume. So he made the following measurements: (1) fill a new oil barrel with water, and the measured mass is 6.5kg. (2) fill the new oil barrel with oil, and the measured mass is 5.5kg. (3) the empty barrel weighs 1.5kg, How much is the diesel oil per kilogram for my uncle? (hint: 1 kilogram per liter of water)

Filled with water, the measured mass is 6.5kg, and the empty barrel weighs 1.5kg
So 6.5-1.5 = 5 kg in water is 5 liters
Amount of oil = 4.2 * 5 = 21 yuan
Oil weight 5.5-1.5 = 4kg
21 / 4 = 5.25 yuan / kg

√24×√42=?

√24×√42=√24×42=√4×6×6×7=12√7