Research on aptitude tests indicates that factors such as coaching and practice for these tests will significantly impact the performance of those individuals who take such tests. The aim of this study is to ascertain the level to which prior knowledge and completion of numerical reasoning tests impacts on individual score on future numerical reasoning tests taken. There were 105 participants. There were two groups. Both groups were given two 13 question numerical reasoning tests, and fourteen minutes to complete each test. There was a fifteen minute interval between the first and second tests. One group was given coaching on how to perform well in numerical reasoning tests during this interval. Analysis indicated that there was a significant difference between results in the first and second tests, suggesting a practice effect. Analysis indicated that there was not a significant difference between the results in group 1 and group 2 on test 2, suggesting that coaching did not affect test scores.