Where has this thing gone? Anyone know?
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|Thu, 01-15-2009 - 10:36pm|
I want to buy one of those multiplication tables that they made in the 80's, the one that has raised semi-transparent buttons with a multiplication problem printed on it, and you can push the button down to reveal the answer underneath. Does anyone have one, or even know what it's called commercially? The patent for it is United States Patent 4258477 under the name "Multiplication Study Device".