Puzzle of Kenken

A Japanese arithmetic puzzle, Sudoku-style

The objective of the game is to fill the NxN grid in with the digits 1 through N such that:

Each row contains exactly one of each digit

Each column contains exactly one of each digit

Each bold-outlined group of cells is a cage containing digits which achieve the specified result using the specified mathematical operation: addition (+), subtraction (−), multiplication (×), and division (÷).