1. Su Doku!

2. Given a grid and some numbers, fill the rest in… 1 2 4 6789 They might be in the wrong order… 6421953

3. Working out which goes where 1 4 2 3 1 The only numbers are 1, 2, 3, 4 You’re going to end up with those numbers once in each column once in each row once in each small block! Let’s start with the bottom left. We can’t have 1 on the bottom row, because it’s already there! We can’t have 4 on the left column, because it’s already there! 1 4

4. 1 4 1 2 3 4 1 Look at the bottom row – what’s missing? What is missing in the bottom right block? What’s missing from that column if 3 goes in the left box? WHOOPS! What’s missing from that column if 4 goes in that left box? Now we’ve got one missing from that right block! What shall we put in there? Let’s look at the right column – what’s missing? Can you finish it off? 2 3 4 4 3 3 2 4

5. Some things to remember 2 31 3 2 1 Remember Sherlock Holmes! 1)“When you’ve eliminated everything else, whatever remains is the truth!” So put your missing numbers in first! 2) “There’s a place for everything!” If 4 is in the red circle, it can’t be in the blue circle, so it must be somewhere else! 3) “Conspicuous by its absence” Each row, column, box has a 1 in, except the third column. So where should the final 1 go? 4 41

6. 4 2 31 31 24 1 1 4 32 243

7. Further practice Now try the practice puzzles available at: http://www.skillsworkshop.org/general/sudokugrids.xls When you have practised why not use one of the blank grids provided to make your own puzzles?