1. The problem is to evaluate the expression in the top-left box: $2.84 + 2.38$. 2. To add two decimal numbers, align the decimal points and add digit by digit. 3. Perform the addition: $$2.84 + 2.38 = 5.22$$ 4. Therefore, the sum of $2.84$ and $2.38$ is $5.22$.