We also study international finance, and ours is Fang Zhizhi's version. I look at the questions here instead of the answers. I understand that the change here is before subtracting the current foreign exchange reserves. Only when I saw the answer did I find that the change of foreign exchange reserves means capital outflow MINUS capital inflow. Your textbook directly defines the changes in foreign exchange reserves. Is this an algorithm? In addition, as far as I know, the balance of payments in our book is the same as that of SAFE, and there are borrowers, with capital outflow being negative and capital inflow being positive. Then if you look at foreign exchange reserves, you can directly look at the international reserve items in the table. The balance in the lender is surplus and the balance is surplus. Also, the subjects and related projects you reserve may be set as equal loans, and the SDR is often 0. Just look at the form of safe, not every country has it, and there is no problem. I suggest you don't memorize the topic. Finding the negative sign of this failing class is the surplus.