Multiplication arrays

The net value is 12.

The net value is 6. The red column and the black next to it zeroate.

 

The net value is -4. The bottom black row and red row next to is zeroates. 

** Students were given a chart of multiplication arrays and built them. 

* Black edge: row or column not flipped

*Red edge: row or column flipped

*2 reds: need to flip twice=black