Backward induction in the decision tree, does anyone understand how the weights are created at the terminal/end nodes?

First Decision Tree: The weights are always after the blue nodes, which look like triangles. The weights are above the numbers that are not equal to 0. For example, the top triangle has a value of 300 and a weight of 0. The value 300 is calculated as -100+(-200)+600=300, so you simply follow the path…