DS7 loves the 2-digit 11s trick, too.

He's good with his 9s, too, though the trick I taught him took longer to sink in than the 11s. Here's what I use:

For any number times 9, look at the non-9. Subtract 1 and you have the 10s place (so for 9x3 => use 3-1=2). Then use that 2 to figure that 2+?=9. That's 7, so 7 goes in the 1s place for an answer of 27.

Simple and quick, and no fingers! wink

Kriston