1, there are 8 packages of sweets, 2 of which are lighter. Li Hong numbered them from ① to ⑧, and then weighed them three times with a balance. The results are as follows: ①+②-③+④, ⑧+⑧-①+⑧, ①+③+①-②+④+⑧. According to these results, can you know which two packages of candy are lighter? Please provide a justification for the answer.

①+② ￠ ③+④ indicates that 3 and 4 are light, and ⑦+⑧+⑤ indicates that 5 and 6 are light.

①+③+⑤￠； ②+④+⑤, if there are 1 light on both sides, the balance will not be unbalanced, and it must be four or six light ones.

So 4, 6 is light.

2. There are two piles of pears, one pile is 14 and the other pile is 13. One pile is relatively heavy, and the others are of the same quality. Give you a balance, and you can guarantee to find this pear at least several times. Tell me about your method.

1. Compare nine. There are nine left. Find out where the heavy one is in nine minutes.

2. The pile of 9 pieces is divided into 3 pieces, each with 3 pieces. Compare two copies. Find out which three rooms.

3. Take two of those three.

So it was three times.

Xiangyun and her four children's homes are on the same side of a street, and several of them are adjacent. The sum of their five house numbers is exactly 100. It is known that Xiangyun has the largest house number. What's his sect number? Why?

On the same side, it should be continuous odd or even.

Set Xiangyun family card X, then the others are x-2, x-4 and x-6.

Column equation

x+x-2+x-4+x-6= 100

4x- 12= 100

x=28

The answer is 28.