6 // Curious Calculations

Curious Calculations Your calculator can do tricks.

(1) Try these multiplications. What do you notice?

161

11611

1116111

111161111

11;111611;111

Does the pattern continue if you use longer strings of 1's?

(2) Enter the number

142;857

(preferably into the memory) and multiply it by 2, 3, 4, 5, 6 and 7. What do you notice?

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Answers on page 252

Triangle of Cards I have 15 cards, numbered consecutively from 1 to 15. I want to lay them out in a triangle. I've put numbers on the top three for later reference:

Triangle of cards.

However, I don't want any old arrangement. I want each card to be the difference between the two cards immediately below it,

two page view?

all devices