Hello!
I'm so sorry that these test results have caused you undue concern. Was any other information shared, e.g. what do they use these results to inform? Are they running any intervention groups as a result of this data?

I think if the school are treating these results as a "snapshot" I wouldn't be too concerned as as you've seen 98 falls within the average range. It's also one of the first more formal tests that your child has taken and many other factors can influence scores. Did they sit paper based tests or online ones? Young children's computer literacy/ spatial reasoning may affect their end result.

As Goldhawk said, I think it's really important to check in with the school. A test like this usually generates a lot of data, which if shared could help you and the school to develop your child's Maths skills.

One thing to keep in mind is that this is a snapshot of one moment in time. As he is in Y1 it is unlikely that he has faced many assessments similar to these before. This is often one of the factors as to why schools start assessments from a young age, to familiarise children with the assessment processes.

Having looked at the front of the autumn term Y1 assessment it covers four areas, number, operations (+/-), measure and geometry. Depending on how the school organises their curriculum they may not have covered much measure or geometry so far this year and may have focused on number work, therefore this may also be a factor.

Is there a PT night coming up where you can ask more in person? If not, ask the teacher for a catch-up before or after school one day and ask them to talk you through it. An explanatory guide to the assessments would be helpful for everyone in the class.

    

    

Given you are paying fees I would push the school to give more context on what these scores mean.
Otherwise what is the point of telling you these scores.

What is the school using this information for?
Is there a score at which children should see additional targeted intervention? eg extra small group maths