9*48+2+6.。。。。。。不是9*47，最好用举例法验证一下

粗心把sum算成了48*9+26,扶额

48*9+2+6=440

找规律
10^3 = 1000 - 74 = 926
10^4 = 10000-74 = 9926
10^5 = 100000 - 74 = 99926
规律：50-2=48个9和26
所以：
48*9+2+6
= 432 + 2 + 6
= 440

一共48个9，不是47个

If 1050 - 74 is written as an integer in base 10 notation, what is the sum of the digits in that integer?如何求解，同学们？