Batting average and strike rate, worked properly.

They count in the runs and not in the divisor. An average is runs divided by the number of times the batter was dismissed, so an innings finished not out adds to the runs without adding to the denominator. That is why a batter with several not-outs can carry a high average on modest scores, and it is the most common mistake in a hand-kept average.

There is not one. The sum is runs divided by dismissals and the divisor is zero, which is undefined rather than infinite or zero. Scorecards usually print a dash, and so does this calculator. Runs per innings is shown alongside, which is a defined number and is often what somebody actually wants in that situation.

Runs scored divided by balls faced, multiplied by a hundred. Seventy-five runs from fifty balls is a strike rate of 150.00. Unlike the average it takes no account of dismissals, so the two figures answer different questions: the average is how much a batter is worth, the strike rate is how quickly they get it.