Missing number problems

​​In a nutshell

Expressions involving an unknown number are needed to solve missing number problems. Unknown numbers are usually represented by letters.

Example 1

$$x + 10 = 12$$

This is the same as asking: "what is added to $$10$$​ to get $$12$$​?"

The answer is $$x=2$$

Note: $$x$$ is the letter commonly used for an unknown.

Method for solving

​​Procedure

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