Let's Make Number Place (Elementary course)
Let's Make Number Place : Step 6
9. Fill in 6s.
Place a 6 on the exposed cell in the bottom center block. If we decide not to put a 6 in the exposed cell in the bottom right block, either of the two cells in the bottom line becomes 6. Then, the marked cell is fixed as 6.
Put a 6 on the exposed cell in the top right block, and the marked cell in the middle right block becomes 6. And it fixes the 6 in the bottom right block --- there were two possibilities but now, the left one becomes 6.
Let's forget 6s for a while. In the meantime, sort out the cells and check if any other figures are fixed, too.
10. In fact, 1s were already fixed.
Let's look at the middle right block. Only one white cell is left which is marked with a red circle. With the 1 in the block below and according to our policy to save exposed cells, the marked cell becomes 1.
Furthermore, the marked cell becomes 1.
Since we have seven 1s fixed, only two 1s are left undecided. According to the fixed 1s, the only possibilities for the two 1s are shown in red circles. They are both exposed cells, but we have no choice...
Then, we have fixed all nine 1s. That means we have 1s and 7s done.
