Green Flag. ** Hold the mouse button down to move the slide ** How to Multiply using this Slide Rule! ******************************************** eg. To multiply 2 x 8. Put the 1 of the slide under the number 2 on the top ruler. Look along to 8 on the slide. Read the answer 16 on the top ruler. * With the slide in this position you can see all the 2 times tables! * eg. To multiply 12 * 30. We multiply 1.2 by 3.0 and adjust the decimal places. Put the 1 of the slide under the number 1.2 on the top ruler. Look along to 3 on the slide. Read the answer 3.6 on the top ruler. The answer is 360 after we adjust the decimal places. Actually you can also choose to put the 10 (rather than the 1) on the slide under the number to multiply by on the rule. For 9 x 8 put the 10 on the slide under the 9 on the rule and read the answer above the 8 on the slide. Of course you can use a slide rule to divide too.
At school @Scratch-Minion learned long multiplication, how to multiply using a book of logarithm tables and how to multiply using a slide rule. He was not taught to multiply on an abacus. Read about Slide Rules at The Slide Rule Museum: http://sliderulemuseum.com/SR_Course.htm Also see Wikipedia: https://en.wikipedia.org/wiki/Slide_rule ** Use a more accurate slide rule at: http://www.antiquark.com/sliderule/sim/n909es/virtual-n909-es.html Our screen is 480 pixels wide limiting the accuracy of this slide rule. Slide rules are usually accurate to 3 significant figures. eg. we could multiply 12 by 24 and get 288. This Scratch Slide Rule is almost accurate to 2 significant figures. eg. if we multiply 12 by 24 we may get 280 or 290. The code used to create the logarithmic rule and slide is inside the project.
