Children are asked addition mental arithmetic questions followed by subtraction then multiplication then division. If a child does not score particularly well in addition, s/he will not be presented with the other areas. If s/he doesn’t score particularly well in subtraction, s/he will not be presented with the other areas. The same applies for multiplication. Your pupils have scored sufficiently well in addition and subtraction to be presented with questions in the other two areas. Some children, particularly younger ones, are proficient at addition and subtraction but less sure of multiplication and division but you have seen the opposite type of pattern in your data. This might be because your teaching has focused on those areas and it has had an impact in comparison with other children of the same age. There is another possibility to be aware of, which is that towards the end of the assessment the children might have been struggling and guessed or taken random choices. The test is multiple choice and they will get some correct by chance. However, to be getting answers consistently correct by guessing is unlikely. Take a look at the pupil scores charts (in custom feedback) for the mental arithmetic modules. If the confidence intervals for multiplication and division are wider than for the other two areas, it suggests that some of the questions were being answered erratically, maybe by random clicking. For example, a child was getting an easy question uncharacteristically wrong and a difficult question uncharacteristically right, they are likely to be guessing rather than calculating.