I am preparing my mother's tax return. She was 94 December 31, 2018. I have prepared the return but the tax calculation seems way off to me. Her taxable income was $70,964 but Turbo tax only calculated a tax of $5,049. She sold a piece of land that led to a $70,000 gain. She held the land for 48 years. Every tax rate I have seen shows at least a 15% tax rate. Concerend that TT is not calculating tax properly. I am thrilled if it is and I am missing a rule concerning her age or length of time land was held.