As you are looking for syllabus for Constable Examination conducted by SSC to join ITBP, so here is complete syllabus:

SSC Constable Exam Syllabus for ITBP
General Intelligence & Reasoning
Arithmetic Number Series.
Relationship concepts.
Spatial Visualization.
Figures Classification.
Analogies.
Visual Memory.
Coding and Decoding
Similarities and Differences.
Spatial Orientation.
Non-verbal series.
Arithmetical Reasoning.
Discrimination.
Observation etc.

GK and General Awareness
Current Affairs – International & National.
General Polity.
Indian & World Geography.
Indian Culture & Heritage.
Indian Economy.
Indian History.
Science & Technology
Events related to India and its neighboring countries.
Indian Constitution etc.

Elementary Mathematics
Fundamental arithmetical operations.
Decimals and Fractions.
Number Systems.
Time and Distance.
Averages.
Interest.
Mensuration.
Computation of Whole Numbers.
Discount.
Ratio and Time.
Percentages.
Ratio and Proportion.
Profit and Loss.
Time and Work etc.

English/Hindi
Vocabulary.
Verbal Ability.
Grammar.
Comprehension etc.