Retirement tax questions

Thanks just a quick follow up , if I end up over $25,000 single income based on your tax table reply , do I get to use home mortgage , personal exemption to bring me back under for the 25,000 max for no taxes or will only the income over the 25,000 be taxable before or after my exemptions for example let’s say I end up at 35,000 after half social security income credit