While preparing for this section in CAT we may need to know the following basics

Decimal Fractions

Decimals and Decimal Places

Equivalent Decimals

Division of Decimals

Multiplication of Decimals

Addition and Subtraction of Decimals

Find the materials in the following link.

http://catdumps.blogspot.com/2009/03/cat-gmat-gre-mba-decimal-fractions.html