Mathematics is often defined as a fundamental science in which numbers and symbols are arranged using a systematic mathematical rule. To understand the concepts of the different theories and rules of mathematics is important but so is the ability to use variety of strategies to perform quick mental calculation. Our students of Grade 4 performed an activity called – Juggling cards, where they played in groups with numbers cards. Each one of the them had to perform simple addition and subtraction calculations to win the cards as quickly as they can. This activity clarified some basic rules of the operations to the student where they came to know the additive property of some common numbers.