Thursday, August 25, 2011

The Eleven Plus and Slide Rules

How many of us remember how to use a slide rule?

Example:

Multiply 52.4 by 0.0316

52.4 = 5.24 X 10 to the power of 1

0.0316 = 3.16 X 10 to the power of -2

1 of C scale against 5.24 on D scale puts 3.16 on C scale off the end of D scale.

10 on C scale against 5.24 on D scale gives 1.656 on D scale against 3.16 on C scale.

5.24 X 3.16 = 1.656 X 10 = 16.56

52.4 X 0.0316 = 16.56 X 10 to the power of 1 – 2

=1.656

Our eleven plus children do long multiplication by a variety of methods. BBC Bitesize shows the `Traditional Method’ and the `Boxes’ method. Parents and children can take their choice! There are sure to be at least three other methods that will work equally well.

Today’s eleven plus children may be tempted to use the calculator on their phone – but sadly not in the examination!

The family attic or grandmother’s sewing box or even grandfather’s shed may hold a long forgotten slide rules. What better way to spend a weekend than cleaning the rule and learning how to use it. The best possible use could be the understanding the value of a slide rule. Parents could point out that stresses on great buildings were worked out on a slide rule. That countless children did their lessons and examinations on slide rules.