Run rate, asking rate, scoring rate

Run rate is a calculation of the average number of runs scored per over. It usually starts to feature in commentaries about half way through each innings in televised limited overs matches particularly, since it can give an indication of the possible final score of the side batting first, and can be used by the side batting second as a guide to pacing their innings.
Very often, with sides batting second, both the required run rate - often called the asking rate - and their actual run rate are displayed simultaneously on the screen to give viewers a comparison of how well they are doing in pursuing the winning target.
Run rate is calculated by dividing the runs scored by the number of overs bowled up until that moment. So, if a side has scored 108 by the end of the eighteenth over in a 40-over match, its run rate is calculated as 108 divided by 18 = 6.00 runs per over. If they were to continue to score at that rate their total by the end of their 40-over innings would be 240 (6.00 x 40).