The sum of 20 and a number is 30

43 20 + n = 30

To find the number that, when added to 20, gives a sum of 30, you can set up an equation.

Let's say the number is represented by the variable "x".

The equation would be: 20 + x = 30.

To solve for "x", you want to isolate it on one side of the equation.

To do this, you can subtract 20 from both sides of the equation:

20 + x - 20 = 30 - 20.

This simplifies to:

x = 10.

So the number that, when added to 20, gives a sum of 30 is 10.