The Friday puzzle (easy): Place a coin in each box (or leave it empty) so that the totals across and down are correct.
3p
5p
10p
8p
6p
4p
The Friday puzzle (harder): Place a digit from 1 to 9 in each box so that the totals across and down are correct. Numbers may not be used more than once in each row or column.
30
10
20
10
20
17
13
(In Japan this sort of thing is called Kakro, in the Guardian Kakuro and in the US Cross Sums. Play online here)
(And did you try my 3-dimensional Sudoku last Friday?)