9 × 6
What is nine times six?
Here's a shortcut: nine is one less than ten, so we can write nine as ten minus one.
First, let's multiply by ten instead, since that's an easy fact: ten times six.
Ten times six is sixty.
But we only wanted nine groups, not ten — so we take away one extra group of six.
Sixty minus six is fifty-four.
So nine times six equals fifty-four! Ten times as many, minus one group, every time.