The sum of two numbers is 76. the first number is 4 more than twice the other. how much is the first number?

Set up two equations, with your first number being x and your second number being y:

Since their sum is 76, then x+y=76.
Since x is 4 more than twice y, then x=4+2y.

Now, since you have a definition for x (x=4+2y), you can substitute that equation in for x in the first equation.
This gets you (4+2y)+y=76.

Now, simplifying that out, you get the solution for y: y=24. Since you know what y is, you can substitute that in for y in the first equation and find x:
x+24=76
x=76-24
x=52