This lecture for Class 3 Mathematics covers essential number operations including addition, subtraction, multiplication, and division. It begins with adding 4-digit numbers both without carrying (when no column exceeds 9) and with carrying (when sums reach 10 or more), explained step-by-step with real-life examples. Subtraction is taught in two forms—without borrowing (when top digits are larger) and with borrowing (regrouping when top digits are smaller). Multiplication concepts include single-digit multiplication, multiplying a 2-digit number by a single digit, and understanding multiplication by 0 and 1 through visuals and stories. Division focuses on dividing 2-digit numbers by a 1-digit number with zero remainder, explained using long division and practical scenarios. The lecture reinforces place value, column methods, and real-life applications to make learning interactive and clear.