Too often the slide rule is presented in a framework completely devoid of mathematics. To multiply 6 by 2, for example, a student is likely to be given a purely manipulative process such as, “Try setting the left index of the C scale on 6 of the D scale. Note that the slide projects so far to the right of the rule that the D scale no longer exists below the 2. When this happens, place the right index of the C scale on the 6 of the D scale. Find 2 on the C scale and below it read the product on the D scale.”