15. each ? below represents a factor between 1 and 9. draw lines to match
each fact on the left with a pattern for its products on the right.
? xo
o in the ones place
? x1
o or 5 in the ones place
? x 2
0,2,4,6, or 8 in the ones place
? x 5
the other factor in the ones place
? x9
1 less than the unknown factor in the tens place