Education for Life software has many subtraction tests for people to practice their maths. You will find 9 standard levels offering 18 tests. The user will get the chance to decide if they want to sit a 20 or 40 question test. There is also a speed test section and 2 extra levels which are designed to be so difficult you should not be too concerned if you do not pass.
The image below is of level 1 subtraction test. The test will give the user 90 seconds to answer as many questions as possible. It will show the user how many you get correct and incorrect. If the user gets 5 or more wrong the test will finish and the user will need to stat again. The user will also get the opportunity to reset the test if they wish by pressing the reset button.