1. Observe two formulas and subtract the second formula from the first formula to get:

○ = 38-22= 16

So □ = 3

2.δ= 5，○ = 3，□ = 1。 The method is to replace δ in the other two formulas with ○ and □, and it is easy to get the result. These three formulas seem a bit complicated. ...

3. Similar to the previous question, if you replace □ with △, you will get △*△ = 4, so △= 2, and then □ = 6.

4. directly change △ into ○, then you get ○+○+○ = 28, that is, seven ○ = 28, then ○ = 4, so △ = 8.

I hope my answer is helpful to you ~O(∩_∩)O~

Come on, kids!