Three jigsaw type puzzles are presented to the subject one at a time and in order of increasing difficulty. Digit symbol test The subject is required to match each one of series of printed digits with an appropriate symbol, using a prescribed code. These are different verbal and nonverbal factors on which questions are framed to test the intelligence of the individual. But this process of determining the intelligence is a complicated process. It involves a comparison and establishment of a relationship between chronological age (CA) and mental age (MA. This relationship is expressed by the term IQ. (Intelligent Quotient) Now we will discuss the concept of age, chronological age & intelligent quotient.