This study aims to describe the students' cognitive and impulsive mathematical representations in solving number patterns problems . Subjects were selected based on the results of tests Matching Familiar Figures Test. The subjects consisted of a student with reflective cognitive-style and a student with cognitive impulsive-style of the same gender and equivalent mathematical ability. This research used the qualitative method. Data collection techniques were done by assigning mathematical problem-solving tasks and task-based interviews. To obtain valid data, the researcher performs the time triangulation.

The results of the study showed that: (1) the mathematical representations of reflective student were (a) recognizing and presenting information visually and verbally, (b) revealing problem-solving strategies through verbal and visual representation, (c) expressing manipulation of mathematical models containing mathematical symbols and formulas according to the formal rules and interpreting the solution verbally, and  (d) looking back the solution through visual representation; (2) the mathematical representations of impulsive student were (a) identifying information visually and presenting information, recognizing, and presenting unknown verbally, (b) revealing and devising a plan through verbal representation and formal notation, (c) expressing manipulations of mathematical models and expressing the interpretation solution verbally, and (d) looking back solutions through verbal representation.