1: We can find a rule, such as: 46*96=64*69, and we can find that the product of two digits and ten digits on both sides is the same, such as 4*9=6*6. The latter is the same, 2*6=3*4, so there are many similar ones, such as 2 1 * 48 = 12 * 84, 3 1 * 39 = 13 * 93, 24 * 84 = 44.

I'm not sure about this, and I don't know if it's right. It should be when you need an accurate answer.

3. The conditions of this question are not clear, so I am not very good at it. sorry

I did all the above by myself. I can't guarantee the accuracy I'm sorry

4: There are one sixth and one fifth.

5. This needs to be used as an auxiliary line to prove that two opposite triangles are similar. If x is set, you probably won't know. Plus there are no letters on your map, which is not easy to do.