How many 2x4 do I need to build a 24x10 room?

To determine how many 2x4s you need for a 24x10 room, first calculate the perimeter of the room: (24 + 10) x 2 = 68 feet. For framing, you'll typically use 2x4s every 16 inches on center along the walls. This means you'll need approximately 12-13 studs for the long walls and 6-7 for the short walls, totaling around 18-20 2x4s, not including extra for door/window framing or additional structural elements.