Let's solve the following mathematical problem:
I thought of a number. To it I added 5. Then I subtracted 3 and got 9. What number did I think of in the beginning?
The first step in solving the problem is to draw a few squares and arrows, over which to write the numbers with the corresponding sign (if the problem says addition, write +, and if it says subtraction, write -).
After filling in the numbers and signs in sequence, it's time for the second step. We need to draw arrows pointing in the opposite direction and rewrite the number, but with the opposite sign. For example, if we have written above the upper arrow -3, then below the lower we must write +3.
Now comes the decision, this is the third step. Solving the problem starts with the number in the last box - in this case it is the number 9.
Answer: 7