## Saturday, June 17, 2006

### Finger Arithmetic Part Four

Continuing finger arithmetic from Part Three. This one is called Part Four. It is the fifth part in the series.

Bigger numbers are added to small numbers. It's an easy lesson that introduces thinking of bigger numbers as the sum of two smaller numbers. One of the smaller numbers is always five. In fact, when you set one of these numbers on a hand, the thumb is the five, and the fingers represent the other small number.

Try two plus seven. Set two. Add the two. Add the five. Read the result (nine). You did say it out loud, right?

Three plus five. Make a fist. Add three fingers. Add the thumb.

All of the examples: 0 + 5, 0 + 6, 0 + 7, 0 + 8, 0 + 9, 1 + 5, 1 + 6, 1 + 7, 1 + 8, 2 + 5, 2 + 6, 2 + 7, 3 + 5, 3 + 6, 4 + 5. Try them all.

Keep practicing Part Three during the week. It takes a bit for the Five's Complements to stick in your head. We'll need to expand on this idea soon. We're trying to keep it down to one new idea a week. However, you need to remember all the old lessons to get it all together.