Working systematically

This Sudoku combines all four arithmetic operations.

You are given the Lowest Common Multiples of sets of digits. Find the digits and then solve the Sudoku.

You need to find the values of the stars before you can apply normal Sudoku rules.

Can you put the numbers 1-5 in the V shape so that both 'arms' have the same total?

If you are given the mean, median and mode of five positive whole numbers, can you find the numbers?

In how many ways can you give change for a ten pence piece?

Place the numbers 1 to 6 in the circles so that each number is the difference between the two numbers just below it.

This is a variation of sudoku which contains a set of special clue-numbers. Each set of 4 small digits stands for the numbers in the four cells of the grid adjacent to this set.

The puzzle can be solved by finding the values of the unknown digits (all indicated by asterisks) in the squares of the $9\times9$ grid.

This grid can be filled so that each of the numbers 1, 2, 3, 4, 5 appears just once in each row, column and diagonal. Which number goes in the centre square?