@1frugalmom, Don't worry about the reading score. I bet your kid just love to read for fun, not read to answer the comprehensive questions. For math, some factors would affect the score significantly:
(1) how familar is the problem?
(2) Any knowledge gap?
(3) how quick to come up with a strategy to solve the problem?
(4) how fast is the calculation especially multiply/divide?
(5) proper calculator usage.