Interesting math story: \x0d\ When Gauss was in elementary school, once after the teacher taught addition, because the teacher wanted to have a rest, he came up with a topic for the students to work out by themselves. The topic is: \ x0d \1+2+3+...+97+98+100. \ x0d \ The teacher is thinking, now the children must count the classes! I used this as an excuse to go out, but Gauss stopped me! ! It turns out that Gauss has worked it out. Little friend, do you know how he did it? \x0d\ Gauss tells you how he worked it out: add 1 to 100 and 100 to 1 and add it up to two lines, which is \ x0d \ 1+2+3+4+...+96+ 100+99+98+97+96+ .....+4+3+2+ 1 \ x0d \ = 10 1+ 10 1+ 10 1+.....+ 10 1+ 10 1+ 1+ 10 1 \ x0d \ * * * 10 1 has 100 sums, but the formula is repeated twice, so the answer obtained by dividing by 10 100 is equal to