Which is just about the way IQ tests work. If you gave me a Weichlser IQ test I'd score lower than I would on a Stanfod Binet. Weichsler measures verbal and mathematical skills. I'm not very good with numbers.
When I was in the second grade, I was given an IQ test. I remember the tester asked me what was the capital of Greece. I remember because I didn't know the answer, and when my mother found out, she was incensed that I had achieved the age of 7 without knowing about Athens and the Athenians. If they'd asked me the capital of Ireland, I could have told them. Dad spent a lot of time telling me about Ireland and the Irish. I'm not sure intelligence can be truly measured.
If you think having a high IQ means you're smart, go to a Mensa meeting.