Smooth Sandstone Crafting Table number doesn't decrease

I would have sandstone and want to make smooth sandstone. I go to the crafting table with a few hundred sandstone. When I hit the crafting table the number over smooth sandstone is, say, 45. I hit the craft button for smooth sandstone. It does create the smooth sandstone, but the number over the smooth sandstone stays at 45. I can make all of my sandstone into smooth sandstone, but that number stays at 45 until I leave the crafting table. I have no idea if I hit the create button enough until I either check my inventory or go back in to the crafting table.