Arithmetic

Place numbers from 1 to N (N being the size of the grid) such that there are no duplicates in rows or columns. Each region has a total that must be reached by applying an operator to all digits in the region.

Fill each region with numbers from 1 to X (X is the size of the region). Numbers outside the grid indicate the sum of that row of column.

Change the top row of numbers into the bottom row of numbers with a series of addition and subtraction operations in each column. Each operation will always result in a single digit.

Fill in numbers from 1 to N (N is the size of the grid) such that there are no duplicates in rows or columns. Circles at intersections have a mathematical operation and a total that is the result for each pair of diagonally adjacent cells.