This is poor. A senior software engineer is not an "average member of the public" (as someone commented). This is basic maths and knowledge of basic maths is

This is poor. A senior software engineer is not an "average member of the public" (as someone commented). This is basic maths and knowledge of basic maths is expected for someone who (I assume) has a Bachelor or Master degree in a maths heavy field. That's definitely a red flag for me.