I see that the income limit is 20,000 for a single person which would seem to attract 4000 tax but the tax credits for a single person is 1,830 x 2 which equates to an income of 18,300 which would suggest that 1,700 income would be taxed on a total income of 20,000. I know i am misreading the figures but out of curiousity someone might put me right.