To convert a natural logarithm to base-10 logarithm, divide by the conversion factor 2.303.

For example, to calculate Log (100): if your calculator yields Ln(100) = 4.60517, then Log(100) = Ln(100)/2.303 = 4.60517/2.303 = 1.9996 (very close to exact answer of 2)

For example, to calculate Log(1.62x10-4), if your calculator yields Ln(1.62x10-4) = -8.728 then Log(1.62x10-4) = Ln(1.62x10-4)/2.303 = -8.728/2.303 = -3.790 (agrees with correct answer)

For example, to calculate Log (100): if your calculator yields Ln(100) = 4.60517, then Log(100) = Ln(100)/2.303 = 4.60517/2.303 = 1.9996 (very close to exact answer of 2)