Why is the calculation wrong? MIUI executives talk about the % of mobile phone calculators

Yesterday, a media reported that "a strange bug appeared in the calculators of many mobile phones. When calculating "10%+10%", the result was not 0.2, but 0.11. Many models including OPPO, Huawei, Apple, vivo, and Xiaomi were affected.

Soon, Xiaomi's product director and general manager of MIUI experience @MIUI Xiaofan came out and published a long article analyzing why the mobile phone calculator would get it wrong by 10%+10%.

@MIUI Xiaofan said that the earliest electronic calculators did not have %, which was added later. As a subsequent improvement, it must have solved the common pain points in calculation scenarios, and it is definitely not a brain-dead thing. He speculated that it was probably a common scenario for Westerners to calculate discounts, tips, interest, etc.

But why did he add "Western computing scenarios" in the beginning? Because he felt that few Chinese people, who have excess computing power, would think and input in this way.

Therefore, the pain point solved by the percent key is not easily used by Chinese people, nor is it easy to think in this way (which is why some people are bored and try 10%+10% today). But for many comrades in the West, this thing can really save lives.

As for why Xiaomi was able to partially calculate 10%+10%=0.2 and partially 10%+10%=0.11, @MIUI小凡 explained:

“In fact, we changed it to 10%+10%=0.2 before, which is why some users’ scientific calculators = 0.2, which is a remnant of the old version, but later we decided to follow the global unified standard.

Because Chinese people don’t usually use % in this way (we directly input 0.1 instead of 10%, which comes with built-in conversion), the change in logic brings little benefit to domestic users, and some people who are used to using % will be upset. After comprehensive consideration, we decided to return to the global standard. ”

I believe that many people will suddenly realize after reading the popular science presentation by MIUI senior officials that a mobile phone calculator actually has such a big secret.