For example, to find log e 2 = 0.693 , press ln 2 on your calculator. Using this method you should find that log e 1 3 = 1.0986 ...

Brent Bridgeman, Anne Harvey, James Braswell, Effects of Calculator Use on Scores on a Test of Mathematical Reasoning, Journal of Educational Measurement, Vol. 32, No. 4 (Winter, 1995), pp. 323-340 ...