died 129 years after A's birthday, A died in 1900 AD, and the sum of the living ages of A and B is 150 years old. In what year was B born?
B逝世于A生日之后129年，A逝世于公元1900年，A、B两人在世的年龄总和为150岁．B出生于公元多少年．
<gadget id="calculator">129 - 150</gadget>
<output>-21</output>

<gadget id="calculator">1_900 + (-21)</gadget>
<output>1_879</output>

<result>1_879</result>