Question

If you multiply me by 3 and increase that value by 3 I am 20. What's my number?

Answer 1

Use x for the unknown value.
Multiply by three: 3x.
Increase that value by 3: 3x +  3

Write an equation: 3x + 3 = 20.
Use the order of operations to solve.
3x + 3 = 20
3x = 17
x = 17/3

The unknown value would be 17/3.

Answer 2

The number is 5.666667.  You can redo the steps using these inverse operations: 20-3=17, then 17/3 to get 5.666667.