Jason bought 7 new baseball trading cards to add to his collection. The next day his dog ate half of his collection. There are now only 39 cards left. How many cards did Jason start with ?

A3-dimensional figure has a square base and 4 lateral faces that meet at a point. explain the difference between the cross sections when a slice is made perpendicular to the base through the vertex, and when a slice is made perpendicular to the base and not through the vertex