有一堆钢管（如图），最上层有6根，最下层有10根，每相邻两层 相差1根，这堆钢管共有多少根？---**Image Description:** The image shows a stack of cylindrical objects, such as logs or pipes, viewed from an angle showing the circular ends on the left. The objects are arranged in horizontal layers, with each upper layer containing fewer objects than the layer below it. The stack forms a shape resembling a trapezoid or a triangular prism viewed from the side. * **Bottom Layer:** Contains 10 cylindrical objects. * **Second Layer from Bottom:** Contains 9 cylindrical objects. * **Third Layer from Bottom:** Contains 8 cylindrical objects. * **Fourth Layer from Bottom:** Contains 7 cylindrical objects. * **Top Layer:** Contains 6 cylindrical objects. The objects are stacked in a compact arrangement where objects in an upper layer rest in the grooves between objects in the layer below.